The two fragments of an unicast packet must have successive sequence numbers to
allow the receiver side to detect matching fragments and merge them again. The
current implementation doesn't provide that property because a sequence of two
atomic_inc_return may be interleaved with another sequence which also changes
the variable.
The access to the fragment sequence number pool has either to be protected by
correct locking or it has to reserve two sequence numbers in a single fetch.
The latter one can easily be done by increasing the value of the last used
sequence number by 2 in a single step. The generated window of two currently
unused sequence numbers can now be scattered across the two fragments.
Reported-by: Linus Lüssing <linus.luessing@web.de>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
We access the data inside the skbs of two fragments directly using memmove
during the merge. The data of the skb could span over multiple skb pages. An
direct access without knowledge about the pages would lead to an invalid memory
access.
Signed-off-by: Sven Eckelmann <sven@narfation.org>
[lindner_marek@yahoo.de: Move return from function to the end]
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
batman_skb_recv can be defined in hard-interface.c as static because it is
never used outside of that file.
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Some function parameters are obsolete now and can be removed.
Reported-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
The routing algorithm must be able to decide if a fragment can be merged with
the missing part and still be passed to a forwarding interface. The fragments
can only differ by one byte in case that the original payload had an uneven
length. In that situation the sender has to inform all possible receivers that
the tail is one byte longer using the flag UNI_FRAG_LARGETAIL.
The combination of UNI_FRAG_LARGETAIL and UNI_FRAG_HEAD flag makes it possible
to calculate the correct length for even and uneven sized payloads.
The original formula missed to add the unicast header at all and forgot to
remove the fragment header of the second fragment. This made the results highly
unreliable and only useful for machines with large differences between the
configured MTUs.
Reported-by: Russell Senior <russell@personaltelco.net>
Reported-by: Marek Lindner <lindner_marek@yahoo.de>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
The routing algorithm must know how large two fragments are to be able to
decide that it is safe to merge them or if it should resubmit without waiting
for the second part. When these two fragments have a too different size, it is
not possible to guess right in every situation.
The user could easily configure the MTU of the attached cards so that one
fragment is forwarded and the other one is added to the fragments table to wait
for the missing part.
For even sized packets, it is possible to split it so that the resulting
packages are equal sized by ignoring the old non-fragment header at the
beginning of the original packet.
This still creates different sized fragments for uneven sized packets.
Reported-by: Russell Senior <russell@personaltelco.net>
Reported-by: Marek Lindner <lindner_marek@yahoo.de>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
The batman-adv vis server has to a stack which stores all information
about packets which should be send later. This stack is protected
with a spinlock that is used to prevent concurrent write access to it.
The send_vis_packets function has to take all elements from the stack
and send them to other hosts over the primary interface. The send will
be initiated without the lock which protects the stack.
The implementation using list_for_each_entry_safe has the problem that
it stores the next element as "safe ptr" to allow the deletion of the
current element in the list. The list may be modified during the
unlock/lock pair in the loop body which may make the safe pointer
not pointing to correct next element.
It is safer to remove and use the first element from the stack until no
elements are available. This does not need reduntant information which
would have to be validated each time the lock was removed.
Reported-by: Russell Senior <russell@personaltelco.net>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
The free_info function will be called when no reference to the info
object exists anymore. It must be ensured that the allocated memory
gets freed and not only the elements which are managed by the info
object.
Signed-off-by: Sven Eckelmann <sven@narfation.org>
A newly created vis info object must be removed when it couldn't be
added to the hash. The old_info which has to be replaced was already
removed and isn't related to the hash anymore.
Signed-off-by: Sven Eckelmann <sven@narfation.org>
The hash_iterate removal introduced a bug leading to a kernel panic when
fetching the vis data on a vis server. That commit forgot to rename one
variable name, which this commit fixes now.
Reported-by: Russell Senior <russell@personaltelco.net>
Signed-off-by: Linus Lüssing <linus.luessing@web.de>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Linux 2.6.21 defines different macros for __attribute__ which are also
used inside batman-adv. The next version of checkpatch.pl warns about
the usage of __attribute__((packed))).
Linux 2.6.33 defines an extra macro __always_unused which is used to
assist source code analyzers and can be used to removed the last
existing __attribute__ inside the source code.
Signed-off-by: Sven Eckelmann <sven@narfation.org>
There's a problem in net/batman-adv/unicast.c::frag_send_skb().
dev_alloc_skb() allocates memory and may fail, thus returning NULL. If
this happens we'll pass a NULL pointer on to skb_split() which in turn
hands it to skb_split_inside_header() from where it gets passed to
skb_put() that lets skb_tail_pointer() play with it and that function
dereferences it. And thus the bat dies.
While I was at it I also moved the call to dev_alloc_skb() above the
assignment to 'unicast_packet' since there's no reason to do that
assignment if the memory allocation fails.
Signed-off-by: Jesper Juhl <jj@chaosbits.net>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
hna_local_fill_buffer must return the number of added hna entries and
not the last checked hash bucket.
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
B.A.T.M.A.N. (better approach to mobile ad-hoc networking) is a routing
protocol for multi-hop ad-hoc mesh networks. The networks may be wired or
wireless. See http://www.open-mesh.org/ for more information and user space
tools.
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Sven Eckelmann
David S. Miller
Simon Wunderlich
Linus Lüssing
Jesper Juhl