batman-adv: mcast: implement multicast packet reception and forwarding

Implement functionality to receive and forward a new TVLV capable
multicast packet type.

The new batman-adv multicast packet type allows to contain several
originator destination addresses within a TVLV. Routers on the way will
potentially split the batman-adv multicast packet and adjust its tracker
TVLV contents.

Routing decisions are still based on the selected BATMAN IV or BATMAN V
routing algorithm. So this new batman-adv multicast packet type retains
the same loop-free properties.

Also a new OGM multicast TVLV flag is introduced to signal to other
nodes that we are capable of handling a batman-adv multicast packet and
multicast tracker TVLV. And that all of our hard interfaces have an MTU
of at least 1280 bytes (IPv6 minimum MTU), as a simple solution for now
to avoid MTU issues while forwarding.

Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

batman-adv: Don't skb_split skbuffs with frag_list

The receiving interface might have used GRO to receive more fragments than
MAX_SKB_FRAGS fragments. In this case, these will not be stored in
skb_shinfo(skb)->frags but merged into the frag list.

batman-adv relies on the function skb_split to split packets up into
multiple smaller packets which are not larger than the MTU on the outgoing
interface. But this function cannot handle frag_list entries and is only
operating on skb_shinfo(skb)->frags. If it is still trying to split such an
skb and xmit'ing it on an interface without support for NETIF_F_FRAGLIST,
then validate_xmit_skb() will try to linearize it. But this fails due to
inconsistent information. And __pskb_pull_tail will trigger a BUG_ON after
skb_copy_bits() returns an error.

In case of entries in frag_list, just linearize the skb before operating on
it with skb_split().

Reported-by: Felix Kaechele <felix@kaechele.ca>
Fixes: c6c8fea29769 ("net: Add batman-adv meshing protocol")
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Tested-by: Felix Kaechele <felix@kaechele.ca>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

batman-adv: Drop NULL check before dropping references

The check if a batman-adv related object is NULL or not is now directly in
the batadv_*_put functions. It is not needed anymore to perform this check
outside these function:

The changes were generated using a coccinelle semantic patch:

@@
expression E;
@@
- if (likely(E != NULL))
(
batadv_backbone_gw_put
|
batadv_claim_put
|
batadv_dat_entry_put
|
batadv_gw_node_put
|
batadv_hardif_neigh_put
|
batadv_hardif_put
|
batadv_nc_node_put
|
batadv_nc_path_put
|
batadv_neigh_ifinfo_put
|
batadv_neigh_node_put
|
batadv_orig_ifinfo_put
|
batadv_orig_node_put
|
batadv_orig_node_vlan_put
|
batadv_softif_vlan_put
|
batadv_tp_vars_put
|
batadv_tt_global_entry_put
|
batadv_tt_local_entry_put
|
batadv_tt_orig_list_entry_put
|
batadv_tt_req_node_put
|
batadv_tvlv_container_put
|
batadv_tvlv_handler_put
)(E);

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

batman-adv: Drop NULL check before dropping references

The check if a batman-adv related object is NULL or not is now directly in
the batadv_*_put functions. It is not needed anymore to perform this check
outside these function:

The changes were generated using a coccinelle semantic patch:

@@
expression E;
@@
- if (likely(E != NULL))
(
batadv_backbone_gw_put
|
batadv_claim_put
|
batadv_dat_entry_put
|
batadv_gw_node_put
|
batadv_hardif_neigh_put
|
batadv_hardif_put
|
batadv_nc_node_put
|
batadv_nc_path_put
|
batadv_neigh_ifinfo_put
|
batadv_neigh_node_put
|
batadv_orig_ifinfo_put
|
batadv_orig_node_put
|
batadv_orig_node_vlan_put
|
batadv_softif_vlan_put
|
batadv_tp_vars_put
|
batadv_tt_global_entry_put
|
batadv_tt_local_entry_put
|
batadv_tt_orig_list_entry_put
|
batadv_tt_req_node_put
|
batadv_tvlv_container_put
|
batadv_tvlv_handler_put
)(E);

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

batman-adv: Drop publication years from copyright info

The batman-adv source code was using the year of publication (to net-next)
as "last" year for the copyright statement. The whole source code mentioned
in the MAINTAINERS "BATMAN ADVANCED" section was handled as a single entity
regarding the publishing year.

This avoided having outdated (in sense of year information - not copyright
holder) publishing information inside several files. But since the simple
"update copyright year" commit (without other changes) in the file was not
well received in the upstream kernel, the option to not have a copyright
year (for initial and last publication) in the files are chosen instead.
More detailed information about the years can still be retrieved from the
SCM system.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Acked-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

batman-adv: Drop unused soft-interface.h include in fragmentation.c

The commit 992b03b88e36 ("batman-adv: Don't always reallocate the
fragmentation skb head") removed the last user of functions from
soft-interface.h.

Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

batman-adv: Add new include for min/max helpers

The commit b296a6d53339 ("kernel.h: split out min()/max() et al. helpers")
moved the min/max helper functionality from kernel.h to minmax.h. Adjust
the kernel code accordingly to avoid fragile indirect includes.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

batman-adv: Don't always reallocate the fragmentation skb head

When a packet is fragmented by batman-adv, the original batman-adv header
is not modified. Only a new fragmentation is inserted between the original
one and the ethernet header. The code must therefore make sure that it has
a writable region of this size in the skbuff head.

But it is not useful to always reallocate the skbuff by this size even when
there would be more than enough headroom still in the skb. The reallocation
is just to costly during in this codepath.

Fixes: ee75ed88879a ("batman-adv: Fragment and send skbs larger than mtu")
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

batman-adv: Reserve needed_*room for fragments

The batadv net_device is trying to propagate the needed_headroom and
needed_tailroom from the lower devices. This is needed to avoid cost
intensive reallocations using pskb_expand_head during the transmission.

But the fragmentation code split the skb's without adding extra room at the
end/beginning of the various fragments. This reduced the performance of
transmissions over complex scenarios (batadv on vxlan on wireguard) because
the lower devices had to perform the reallocations at least once.

Fixes: ee75ed88879a ("batman-adv: Fragment and send skbs larger than mtu")
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

batman-adv: Drop repeated words in comments

checkpatch found various instances of "Possible repeated word" in various
comments.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

batman-adv: Fix typos and grammar in documentation

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

batman-adv: Update copyright years for 2020

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

batman-adv: Drop license boilerplate

All files got a SPDX-License-Identifier with commit 7db7d9f369a4
("batman-adv: Add SPDX license identifier above copyright header"). All the
required information about the license conditions can be found in
LICENSES/.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

batman-adv: Update copyright years for 2019

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

batman-adv: Expand merged fragment buffer for full packet

The complete size ("total_size") of the fragmented packet is stored in the
fragment header and in the size of the fragment chain. When the fragments
are ready for merge, the skbuff's tail of the first fragment is expanded to
have enough room after the data pointer for at least total_size. This means
that it gets expanded by total_size - first_skb->len.

But this is ignoring the fact that after expanding the buffer, the fragment
header is pulled by from this buffer. Assuming that the tailroom of the
buffer was already 0, the buffer after the data pointer of the skbuff is
now only total_size - len(fragment_header) large. When the merge function
is then processing the remaining fragments, the code to copy the data over
to the merged skbuff will cause an skb_over_panic when it tries to actually
put enough data to fill the total_size bytes of the packet.

The size of the skb_pull must therefore also be taken into account when the
buffer's tailroom is expanded.

Fixes: 610bfc6bc99b ("batman-adv: Receive fragmented packets and merge")
Reported-by: Martin Weinelt <martin@darmstadt.freifunk.net>
Co-authored-by: Linus Lüssing <linus.luessing@c0d3.blue>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

batman-adv: Update copyright years for 2018

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

batman-adv: invalidate checksum on fragment reassembly

A more sophisticated implementation could try to combine fragment checksums
when all fragments have CHECKSUM_COMPLETE and are split at even offsets.
For now, we just set ip_summed to CHECKSUM_NONE to avoid "hw csum failure"
warnings in the kernel log when fragmented frames are received. In
consequence, skb_pull_rcsum() can be replaced with skb_pull().

Note that in usual setups, packets don't reach batman-adv with
CHECKSUM_COMPLETE (I assume NICs bail out of checksumming when they see
batadv's ethtype?), which is why the log messages do not occur on every
system using batman-adv. I could reproduce this issue by stacking
batman-adv on top of a VXLAN interface.

Fixes: 610bfc6bc99b ("batman-adv: Receive fragmented packets and merge")
Tested-by: Maximilian Wilhelm <max@sdn.clinic>
Signed-off-by: Matthias Schiffer <mschiffer@universe-factory.net>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

batman-adv: Convert packet.h to uapi header

The header file is used by different userspace programs to inject packets
or to decode sniffed packets. It should therefore be available to them as
userspace header.

Also other components in the kernel (like the flow dissector) require
access to the packet definitions to be able to decode ETH_P_BATMAN ethernet
packets.

Signed-off-by: Sven Eckelmann <sven.eckelmann@openmesh.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

batman-adv: Use parentheses in function kernel-doc

The documentation describing kernel-doc comments for functions ("How to
format kernel-doc comments") uses parentheses at the end of the function
name. Using this format allows to use a consistent style when adding
documentation to a function and when referencing this function in a
different kernel-doc section.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

batman-adv: include gfp.h for GFP_* defines

The linux/gfp.h provides the GFP_ATOMIC and GFP_KERNEL define. It should
therefore be included instead of linux/fs.h.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

batman-adv: Add SPDX license identifier above copyright header

The "Linux kernel licensing rules" require that each file has a SPDX
license identifier as first line (and sometimes as second line).

The FSFE REUSE practices [1] would also require the same tags but have no
restrictions on the placement in the source file. Using the "Linux kernel
licensing rules" is therefore also fulfilling the FSFE REUSE practices
requirements at the same time.

[1] https://reuse.software/practices/

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

batman-adv: Always initialize fragment header priority

The batman-adv unuicast fragment header contains 3 bits for the priority of
the packet. These bits will be initialized when the skb->priority contains
a value between 256 and 263. But otherwise, the uninitialized bits from the
stack will be used.

Fixes: c0f25c802b33 ("batman-adv: Include frame priority in fragment header")
Signed-off-by: Sven Eckelmann <sven.eckelmann@open-mesh.com>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

networking: introduce and use skb_put_data()

A common pattern with skb_put() is to just want to memcpy()
some data into the new space, introduce skb_put_data() for
this.

An spatch similar to the one for skb_put_zero() converts many
of the places using it:

@@
identifier p, p2;
expression len, skb, data;
type t, t2;
@@
(
-p = skb_put(skb, len);
+p = skb_put_data(skb, data, len);
|
-p = (t)skb_put(skb, len);
+p = skb_put_data(skb, data, len);
)
(
p2 = (t2)p;
-memcpy(p2, data, len);
|
-memcpy(p, data, len);
)

@@
type t, t2;
identifier p, p2;
expression skb, data;
@@
t *p;
...
(
-p = skb_put(skb, sizeof(t));
+p = skb_put_data(skb, data, sizeof(t));
|
-p = (t *)skb_put(skb, sizeof(t));
+p = skb_put_data(skb, data, sizeof(t));
)
(
p2 = (t2)p;
-memcpy(p2, data, sizeof(*p));
|
-memcpy(p, data, sizeof(*p));
)

@@
expression skb, len, data;
@@
-memcpy(skb_put(skb, len), data, len);
+skb_put_data(skb, data, len);

(again, manually post-processed to retain some comments)

Reviewed-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

batman-adv: Keep fragments equally sized

The batman-adv fragmentation packets have the design problem that they
cannot be refragmented and cannot handle padding by the underlying link.
The latter often leads to problems when networks are incorrectly configured
and don't use a common MTU.

The sender could for example fragment a 1271 byte frame (plus external
ethernet header (14) and batadv unicast header (10)) to fit in a 1280 bytes
large MTU of the underlying link (max. 1294 byte frames). This would create
a 1294 bytes large frame (fragment 2) and a 55 bytes large frame
(fragment 1). The extra 54 bytes are the fragment header (20) added to each
fragment and the external ethernet header (14) for the second fragment.

Let us assume that the next hop is then not able to transport 1294 bytes to
its next hop. The 1294 byte large frame will be dropped but the 55 bytes
large fragment will still be forwarded to its destination.

Or let us assume that the underlying hardware requires that each frame has
a minimum size (e.g. 60 bytes). Then it will pad the 55 bytes frame to 60
bytes. The receiver of the 60 bytes frame will no longer be able to
correctly assemble the two frames together because it is not aware that 5
bytes of the 60 bytes frame are padding and don't belong to the reassembled
frame.

This can partly be avoided by splitting frames more equally. In this
example, the 675 and 674 bytes large fragment frames could both potentially
reach its destination without being too large or too small.

Reported-by: Martin Weinelt <martin@darmstadt.freifunk.net>
Fixes: ee75ed88879a ("batman-adv: Fragment and send skbs larger than mtu")
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Acked-by: Linus Lüssing <linus.luessing@c0d3.blue>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

batman-adv: Fix transmission of final, 16th fragment

Trying to split and transmit a unicast packet in 16 parts will fail for
the final fragment: After having sent the 15th one with a frag_packet.no
index of 14, we will increase the the index to 15 - and return with an
error code immediately, even though one more fragment is due for
transmission and allowed.

Fixing this issue by moving the check before incrementing the index.

While at it, adding an unlikely(), because the check is actually more of
an assertion.

Fixes: ee75ed88879a ("batman-adv: Fragment and send skbs larger than mtu")
Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

batman-adv: Fix double free during fragment merge error

The function batadv_frag_skb_buffer was supposed not to consume the skbuff
on errors. This was followed in the helper function
batadv_frag_insert_packet when the skb would potentially be inserted in the
fragment queue. But it could happen that the next helper function
batadv_frag_merge_packets would try to merge the fragments and fail. This
results in a kfree_skb of all the enqueued fragments (including the just
inserted one). batadv_recv_frag_packet would detect the error in
batadv_frag_skb_buffer and try to free the skb again.

The behavior of batadv_frag_skb_buffer (and its helper
batadv_frag_insert_packet) must therefore be changed to always consume the
skbuff to have a common behavior and avoid the double kfree_skb.

Fixes: 610bfc6bc99b ("batman-adv: Receive fragmented packets and merge")
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

batman-adv: update copyright years for 2017

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

batman-adv: Decrease hardif refcnt on fragmentation send error

An error before the hardif is found has to free the skb. But every error
after that has to free the skb + put the hard interface.

Fixes: 8def0be82dd1 ("batman-adv: Consume skb in batadv_frag_send_packet")
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

batman-adv: Consume skb in batadv_frag_send_packet

Sending functions in Linux consume the supplied skbuff. Doing the same in
batadv_frag_send_packet avoids the hack of returning -1 (-EPERM) to signal
the caller that he is responsible for cleaning up the skb.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

batman-adv: use consume_skb for non-dropped packets

kfree_skb assumes that an skb is dropped after an failure and notes that.
consume_skb should be used in non-failure situations. Such information is
important for dropmonitor netlink which tells how many packets were dropped
and where this drop happened.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

batman-adv: Use proper name for fragments list head

The batman-adv codebase is using "list" for the list node (prev/next) and
<list content descriptor>+"_list" for the head of a list. Not using this
naming scheme can up in confusions because list_head is used for both the
head of the list and the list node (prev/next) in each item of the list.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

batman-adv: Remove needless init of variables on stack

Some variables are overwritten immediatelly in a functions. These don't
have to be initialized to a specific value on the stack because the value
will be overwritten before they will be used anywhere.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

batman-adv: return netdev status in the TX path

Return the proper netdev TX status along the TX path so that the tp_meter
can understand when the queue is full and should stop sending packets.

Signed-off-by: Antonio Quartulli <antonio.quartulli@open-mesh.com>
Signed-off-by: Sven Eckelmann <sven.eckelmann@open-mesh.com>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

batman-adv: Include frame priority in fragment header

Unfragmented frames which traverse a node have their skb->priority set
by looking at the IP ToS byte, or the 802.1p header. However for
fragments this is not possible, only one of the fragments will contain
the headers. Instead, place the priority into the fragment header and
on receiving a fragment, use this information to set the skb->priority
for when the fragment is forwarded.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

batman-adv: Set skb priority in fragments

BATMAN will set the skb->priority based on the IP precedence or 802.1q
tag. However, if it needs to fragment the frame, it currently leaves
the fragment skb with the default priority and actually overwrites the
priority in the unfragmented frame. Fix this.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

batman-adv: Fix checkpatch warning about 'unsigned' type

checkpatch.pl warns about the use of 'unsigned' as a short form for
'unsigned int'.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Antonio Quartulli <a@unstable.cc>

batman-adv: keep track of when unicast packets are sent

To enable ELP to send probing packets over wireless links
only if needed, batman-adv must keep track of the last time
it sent a unicast packet towards every neighbour.

For this purpose a 2 main changes are introduced:
1) a new member of the elp_neigh_node structure stores the
last time a unicast packet was sent towards this neighbour;
2) a wrapper function for sending unicast packets is
implemented. This function will simply update the member
describe din point 1) and then forward the packet to the
real sending routine.

Point 2) implies that any code-path leading to a unicast
sending now has to use the new wrapper.

Signed-off-by: Antonio Quartulli <antonio@open-mesh.com>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>

batman-adv: Rename batadv_neigh_node *_free_ref function to *_put

The batman-adv source code is the only place in the kernel which uses the
*_free_ref naming scheme for the *_put functions. Changing it to *_put
makes it more consistent and makes it easier to understand the connection
to the *_get functions.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Antonio Quartulli <a@unstable.cc>

batman-adv: Rename batadv_hardif *_free_ref function to *_put

The batman-adv source code is the only place in the kernel which uses the
*_free_ref naming scheme for the *_put functions. Changing it to *_put
makes it more consistent and makes it easier to understand the connection
to the *_get functions.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Antonio Quartulli <a@unstable.cc>

batman-adv: Rename batadv_orig_node *_free_ref function to *_put

The batman-adv source code is the only place in the kernel which uses the
*_free_ref naming scheme for the *_put functions. Changing it to *_put
makes it more consistent and makes it easier to understand the connection
to the *_get functions.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Antonio Quartulli <a@unstable.cc>

batman-adv: update copyright years for 2016

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Antonio Quartulli <a@unstable.cc>

batman-adv: Fix kerneldoc parsing of return description

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Antonio Quartulli <a@unstable.cc>

batman-adv: Remove kerneldoc for missing parameters

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Antonio Quartulli <a@unstable.cc>

batman-adv: Use chain pointer when purging fragments

The chain pointer was already created in batadv_frag_purge_orig to make the
checks more readable. Just use the chain pointer everywhere instead of
having the same dereference + array access in the most lines of this
function.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Acked-by: Martin Hundebøll <martin@hundeboll.net>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Antonio Quartulli <antonio@meshcoding.com>

batman-adv: Add lockdep_asserts for documented external locks

Some functions already have documentation about locks they require inside
their kerneldoc header. These can be directly tested during runtime using
the lockdep asserts.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Antonio Quartulli <antonio@meshcoding.com>

batman-adv: Replace C99 int types with kernel type

(s|u)(8|16|32|64) are the preferred types in the kernel. The use of the
standard C99 types u?int(8|16|32|64)_t are objected by some people and even
checkpatch now warns about using them.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Antonio Quartulli <antonio@meshcoding.com>

batman-adv: Add required includes to all files

The header files could not be build indepdent from each other. This is
happened because headers didn't include the files for things they've used.
This was problematic because the success of a build depended on the
knowledge about the right order of local includes.

Also source files were not including everything they've used explicitly.
Instead they required that transitive includes are always stable. This is
problematic because some transitive includes are not obvious, depend on
config settings and may not be stable in the future.

The order for include blocks are:

* primary headers (main.h and the *.h file of a *.c file)
* global linux headers
* required local headers
* extra forward declarations for pointers in function/struct declarations

The only exceptions are linux/bitops.h and linux/if_ether.h in packet.h.
This header file is shared with userspace applications like batctl and must
therefore build together with userspace applications. The header
linux/bitops.h is not part of the uapi headers and linux/if_ether.h
conflicts with the musl implementation of netinet/if_ether.h. The
maintainers rejected the use of __KERNEL__ preprocessor checks and thus
these two headers are only in main.h. All files using packet.h first have
to include main.h to work correctly.

Reported-by: Markus Pargmann <mpa@pengutronix.de>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>

batman-adv: Use only queued fragments when merging

The fragment queueing code now validates the total_size of each fragment,
checks when enough fragments are queued to allow to merge them into a
single packet and if the fragments have the correct size. Therefore, it is
not required to have any other parameter for the merging function than a
list of queued fragments.

This change should avoid problems like in the past when the different skb
from the list and the function parameter were mixed incorrectly.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Acked-by: Martin Hundebøll <martin@hundeboll.net>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>

batman-adv: Check total_size when queueing fragments

The fragmentation code was replaced in
610bfc6bc99bc83680d190ebc69359a05fc7f605 ("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: Sven Eckelmann <sven@narfation.org>
Acked-by: Martin Hundebøll <martin@hundeboll.net>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>

batman-adv: update copyright years for 2015

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

batman-adv: checkpatch - Please don't use multiple blank lines

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

batman-adv: Unify fragment size calculation

The fragmentation code was replaced in 610bfc6bc99bc83680d190ebc69359a05fc7f605
("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: Sven Eckelmann <sven@narfation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

batman-adv: Calculate extra tail size based on queued fragments

The fragmentation code was replaced in 610bfc6bc99bc83680d190ebc69359a05fc7f605
("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: Philipp Psurek <philipp.psurek@gmail.com>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Acked-by: Martin Hundebøll <martin@hundeboll.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

batman-adv: Fix parameter order of hlist_add_behind

1d023284c31a4e40a94d5bbcb7dbb7a35ee0bcbc ("list: fix order of arguments for
hlist_add_after(_rcu)") was incorrectly rebased on top of
d9124268d84a836f14a6ead54ff9d8eee4c43be5 ("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: Sven Eckelmann <sven@narfation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

list: fix order of arguments for hlist_add_after(_rcu)

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: Ken 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

batman-adv: Fix out-of-order fragmentation support

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 610bfc6bc99bc83680d190ebc69359a05fc7f605
("batman-adv: Receive fragmented packets and merge").

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Antonio Quartulli <antonio@meshcoding.com>

batman-adv: fix reference counting imbalance while sending fragment

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 ee75ed88879af88558818a5c6609d85f60ff0df4
("batman-adv: Fragment and send skbs larger than mtu")

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

batman-adv: prefer ether_addr_copy to memcpy

On some architectures ether_addr_copy() is slightly faster
than memcpy() therefore use the former when possible.

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

batman-adv: update copyright years for 2014

Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Antonio Quartulli <antonio@meshcoding.com>

batman-adv: remove FSF address from GPL disclaimer

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

batman-adv: fix header alignment by unrolling batadv_header

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: Russell King <linux@arm.linux.org.uk>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Antonio Quartulli <antonio@meshcoding.com>

batman-adv: Fragment and send skbs larger than mtu

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: Martin Hundebøll <martin@hundeboll.net>
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
Signed-off-by: Antonio Quartulli <antonio@meshcoding.com>

batman-adv: Receive fragmented packets and merge

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: Martin Hundebøll <martin@hundeboll.net>
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
Signed-off-by: Antonio Quartulli <antonio@meshcoding.com>