6lowpan: handling 6lowpan fragmentation via inet_frag api

This patch drops the current way of 6lowpan fragmentation on receiving
side and replace it with a implementation which use the inet_frag api.
The old fragmentation handling has some race conditions and isn't
rfc4944 compatible. Also adding support to match fragments on
destination address, source address, tag value and datagram_size
which is missing in the current implementation.

Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 66 insertions, 0 deletions

diff --git a/net/ieee802154/reassembly.h b/net/ieee802154/reassembly.h
new file mode 100644
index 000000000000..055518b9da2d
--- /dev/null
+++ b/net/ieee802154/reassembly.h
@@ -0,0 +1,66 @@
+#ifndef __IEEE802154_6LOWPAN_REASSEMBLY_H__
+#define __IEEE802154_6LOWPAN_REASSEMBLY_H__
+
+#include <net/inet_frag.h>
+
+struct lowpan_create_arg {
+        __be16 tag;
+        u16 d_size;
+        const struct ieee802154_addr *src;
+        const struct ieee802154_addr *dst;
+};
+
+/* Equivalent of ipv4 struct ip
+ */
+struct lowpan_frag_queue {
+        struct inet_frag_queue  q;
+
+        __be16                  tag;
+        u16                     d_size;
+        struct ieee802154_addr  saddr;
+        struct ieee802154_addr  daddr;
+};
+
+static inline u32 ieee802154_addr_hash(const struct ieee802154_addr *a)
+{
+        switch (a->addr_type) {
+        case IEEE802154_ADDR_LONG:
+                return (__force u32)((((u32 *)a->hwaddr))[0] ^
+                                      ((u32 *)(a->hwaddr))[1]);
+        case IEEE802154_ADDR_SHORT:
+                return (__force u32)(a->short_addr);
+        default:
+                return 0;
+        }
+}
+
+static inline bool ieee802154_addr_addr_equal(const struct ieee802154_addr *a1,
+                                   const struct ieee802154_addr *a2)
+{
+        if (a1->pan_id != a2->pan_id)
+                return false;
+
+        if (a1->addr_type != a2->addr_type)
+                return false;
+
+        switch (a1->addr_type) {
+        case IEEE802154_ADDR_LONG:
+                if (memcmp(a1->hwaddr, a2->hwaddr, IEEE802154_ADDR_LEN))
+                        return false;
+                break;
+        case IEEE802154_ADDR_SHORT:
+                if (a1->short_addr != a2->short_addr)
+                        return false;
+                break;
+        default:
+                return false;
+        }
+
+        return true;
+}
+
+int lowpan_frag_rcv(struct sk_buff *skb, const u8 frag_type);
+void lowpan_net_frag_exit(void);
+int lowpan_net_frag_init(void);
+
+#endif /* __IEEE802154_6LOWPAN_REASSEMBLY_H__ */