Merge branch 'ipv6-defrag-rbtree'

Peter Oskolkov says:

====================
net: IP defrag: use rbtrees in IPv6 defragmentation

Currently, IPv6 defragmentation code drops non-last fragments that
are smaller than 1280 bytes: see
commit 0ed4229b08c1 ("ipv6: defrag: drop non-last frags smaller than min mtu")

This behavior is not specified in IPv6 RFCs and appears to break compatibility
with some IPv6 implementations, as reported here:
https://www.spinics.net/lists/netdev/msg543846.html

This patchset contains four patches:
- patch 1 moves rbtree-related code from IPv4 to files shared b/w
IPv4/IPv6
- patch 2 changes IPv6 defragmenation code to use rbtrees for defrag
queue
- patch 3 changes nf_conntrack IPv6 defragmentation code to use rbtrees
- patch 4 changes ip_defrag selftest to test changes made in the
previous three patches.

Along the way, the 1280-byte restrictions are removed.

I plan to introduce similar changes to 6lowpan defragmentation code
once I figure out how to test it.
====================

Reviewed-by: Eric Dumazet <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

1 files changed, 14 insertions, 2 deletions

diff --git a/include/net/inet_frag.h b/include/net/inet_frag.h
index 1662cbc0b46b..b02bf737d019 100644
--- a/include/net/inet_frag.h
+++ b/include/net/inet_frag.h
@@ -77,8 +77,8 @@ struct inet_frag_queue {
 	struct timer_list	timer;
 	spinlock_t		lock;
 	refcount_t		refcnt;
-	struct sk_buff		*fragments;  /* Used in IPv6. */
-	struct rb_root		rb_fragments; /* Used in IPv4. */
+	struct sk_buff		*fragments;  /* used in 6lopwpan IPv6. */
+	struct rb_root		rb_fragments; /* Used in IPv4/IPv6. */
 	struct sk_buff		*fragments_tail;
 	struct sk_buff		*last_run_head;
 	ktime_t			stamp;
@@ -153,4 +153,16 @@ static inline void add_frag_mem_limit(struct netns_frags *nf, long val)
 
 extern const u8 ip_frag_ecn_table[16];
 
+/* Return values of inet_frag_queue_insert() */
+#define IPFRAG_OK	0
+#define IPFRAG_DUP	1
+#define IPFRAG_OVERLAP	2
+int inet_frag_queue_insert(struct inet_frag_queue *q, struct sk_buff *skb,
+			   int offset, int end);
+void *inet_frag_reasm_prepare(struct inet_frag_queue *q, struct sk_buff *skb,
+			      struct sk_buff *parent);
+void inet_frag_reasm_finish(struct inet_frag_queue *q, struct sk_buff *head,
+			    void *reasm_data);
+struct sk_buff *inet_frag_pull_head(struct inet_frag_queue *q);
+
 #endif