The fragmentation code was replaced in
610bfc6b ("batman-adv: Receive fragmented
packets and merge") by an implementation which handles the queueing+merging
of fragments based on their size and the total_size of the non-fragmented
packet. This total_size is announced by each fragment. The new
implementation doesn't check if the the total_size information of the
packets inside one chain is consistent.

This is consistency check is recommended to allow using any of the packets
in the queue to decide whether all fragments of a packet are received or
not.
Signed-off-by: NSven Eckelmann <sven@narfation.org>
Acked-by: NMartin Hundebøll <martin@hundeboll.net>
Signed-off-by: NMarek Lindner <mareklindner@neomailbox.ch>

Signed-off-by: NSven Eckelmann <sven@narfation.org>
Signed-off-by: NMarek Lindner <mareklindner@neomailbox.ch>

Signed-off-by: NAntonio Quartulli <antonio@meshcoding.com>
Signed-off-by: NMarek Lindner <mareklindner@neomailbox.ch>

The fragmentation code was replaced in 610bfc6b
("batman-adv: Receive fragmented packets and merge") by an implementation which
can handle up to 16 fragments of a packet. The packet is prepared for the split
in fragments by the function batadv_frag_send_packet and the actual split is
done by batadv_frag_create.

Both functions calculate the size of a fragment themself. But their calculation
differs because batadv_frag_send_packet also subtracts ETH_HLEN. Therefore,
the check in batadv_frag_send_packet "can a full fragment can be created?" may
return true even when batadv_frag_create cannot create a full fragment.

The function batadv_frag_create doesn't check the size of the skb before
splitting it and therefore might try to create a larger fragment than the
remaining buffer. This creates an integer underflow and an invalid len is given
to skb_split.
Signed-off-by: NSven Eckelmann <sven@narfation.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The fragmentation code was replaced in 610bfc6b
("batman-adv: Receive fragmented packets and merge"). The new code provided a
mostly unused parameter skb for the merging function. It is used inside the
function to calculate the additionally needed skb tailroom. But instead of
increasing its own tailroom, it is only increasing the tailroom of the first
queued skb. This is not correct in some situations because the first queued
entry can be a different one than the parameter.

An observed problem was:

1. packet with size 104, total_size 1464, fragno 1 was received
   - packet is queued
2. packet with size 1400, total_size 1464, fragno 0 was received
   - packet is queued at the end of the list
3. enough data was received and can be given to the merge function
   (1464 == (1400 - 20) + (104 - 20))
   - merge functions gets 1400 byte large packet as skb argument
4. merge function gets first entry in queue (104 byte)
   - stored as skb_out
5. merge function calculates the required extra tail as total_size - skb->len
   - pskb_expand_head tail of skb_out with 64 bytes
6. merge function tries to squeeze the extra 1380 bytes from the second queued
   skb (1400 byte aka skb parameter) in the 64 extra tail bytes of skb_out

Instead calculate the extra required tail bytes for skb_out also using skb_out
instead of using the parameter skb. The skb parameter is only used to get the
total_size from the last received packet. This is also the total_size used to
decide that all fragments were received.
Reported-by: NPhilipp Psurek <philipp.psurek@gmail.com>
Signed-off-by: NSven Eckelmann <sven@narfation.org>
Acked-by: NMartin Hundebøll <martin@hundeboll.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

1d023284 ("list: fix order of arguments for
hlist_add_after(_rcu)") was incorrectly rebased on top of
d9124268 ("batman-adv: Fix out-of-order
fragmentation support"). The parameter order change of the rebased patch was
not re-applied as expected. This causes a memory leak and can cause crashes
when out-of-order packets are received. hlist_add_behind will try to access the
uninitalized list pointers of frag_entry_new to find the previous/next entry
and may modify/read random memory locations.
Signed-off-by: NSven Eckelmann <sven@narfation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

All other add functions for lists have the new item as first argument
and the position where it is added as second argument.  This was changed
for no good reason in this function and makes using it unnecessary
confusing.

The name was changed to hlist_add_behind() to cause unconverted code to
generate a compile error instead of using the wrong parameter order.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: NKen Helias <kenhelias@firemail.de>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Acked-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>	[intel driver bits]
Cc: Hugh Dickins <hughd@google.com>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

batadv_frag_insert_packet was unable to handle out-of-order packets because it
dropped them directly. This is caused by the way the fragmentation lists is
checked for the correct place to insert a fragmentation entry.

The fragmentation code keeps the fragments in lists. The fragmentation entries
are kept in descending order of sequence number. The list is traversed and each
entry is compared with the new fragment. If the current entry has a smaller
sequence number than the new fragment then the new one has to be inserted
before the current entry. This ensures that the list is still in descending
order.

An out-of-order packet with a smaller sequence number than all entries in the
list still has to be added to the end of the list. The used hlist has no
information about the last entry in the list inside hlist_head and thus the
last entry has to be calculated differently. Currently the code assumes that
the iterator variable of hlist_for_each_entry can be used for this purpose
after the hlist_for_each_entry finished. This is obviously wrong because the
iterator variable is always NULL when the list was completely traversed.

Instead the information about the last entry has to be stored in a different
variable.

This problem was introduced in 610bfc6b
("batman-adv: Receive fragmented packets and merge").
Signed-off-by: NSven Eckelmann <sven@narfation.org>
Signed-off-by: NMarek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: NAntonio Quartulli <antonio@meshcoding.com>

In the new fragmentation code the batadv_frag_send_packet()
function obtains a reference to the primary_if, but it does
not release it upon return.

This reference imbalance prevents the primary_if (and then
the related netdevice) to be properly released on shut down.

Fix this by releasing the primary_if in batadv_frag_send_packet().

Introduced by ee75ed88
("batman-adv: Fragment and send skbs larger than mtu")

Cc: Martin Hundebøll <martin@hundeboll.net>
Signed-off-by: NAntonio Quartulli <antonio@open-mesh.com>
Signed-off-by: NMarek Lindner <mareklindner@neomailbox.ch>
Acked-by: NMartin Hundebøll <martin@hundeboll.net>

On some architectures ether_addr_copy() is slightly faster
than memcpy() therefore use the former when possible.
Signed-off-by: NAntonio Quartulli <antonio@meshcoding.com>
Signed-off-by: NMarek Lindner <mareklindner@neomailbox.ch>

Signed-off-by: NSimon Wunderlich <sw@simonwunderlich.de>
Signed-off-by: NMarek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: NAntonio Quartulli <antonio@meshcoding.com>

As suggested by checkpatch, remove all the references to the
FSF address since the kernel already has one reference in
its documentation.

In this way it is easier to update it in case of future
changes.
Signed-off-by: NAntonio Quartulli <antonio@meshcoding.com>
Signed-off-by: NMarek Lindner <mareklindner@neomailbox.ch>

The size of the batadv_header of 3 is problematic on some architectures
which automatically pad all structures to a 32 bit boundary. To not lose
performance by packing this struct, better embed it into the various
host structures.
Reported-by: NRussell King <linux@arm.linux.org.uk>
Signed-off-by: NSimon Wunderlich <sw@simonwunderlich.de>
Signed-off-by: NMarek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: NAntonio Quartulli <antonio@meshcoding.com>

Non-broadcast packets larger than MTU are fragmented and sent with
an encapsulating header. Up to 16 fragments are supported, which are
sent in reverse order on the wire to allow minimal memory copying when
creating fragments.
Signed-off-by: NMartin Hundebøll <martin@hundeboll.net>
Signed-off-by: NMarek Lindner <lindner_marek@yahoo.de>
Signed-off-by: NAntonio Quartulli <antonio@meshcoding.com>

Fragments arriving at their destination are buffered for later merge.
Merged packets are passed to the main receive function as had they never
been fragmented.

Fragments are forwarded without merging if the MTU of the outgoing
interface is smaller than the size of the merged packet.
Signed-off-by: NMartin Hundebøll <martin@hundeboll.net>
Signed-off-by: NMarek Lindner <lindner_marek@yahoo.de>
Signed-off-by: NAntonio Quartulli <antonio@meshcoding.com>