kernel/net/batman-adv/bat_iv_ogm.c, branch master

batman-adv: avoid OGM aggregation when skb tailroom is insufficient

2026-03-14T07:29:47Z

When OGM aggregation state is toggled at runtime, an existing forwarded packet may have been allocated with only packet_len bytes, while a later packet can still be selected for aggregation. Appending in this case can hit skb_put overflow conditions. Reject aggregation when the target skb tailroom cannot accommodate the new packet. The caller then falls back to creating a new forward packet instead of appending. Fixes: c6c8fea29769 ("net: Add batman-adv meshing protocol") Cc: stable@vger.kernel.org Reported-by: Yifan Wu Reported-by: Juefei Pu Signed-off-by: Yuan Tan Signed-off-by: Xin Liu Signed-off-by: Ao Zhou Signed-off-by: Yang Yang Signed-off-by: Sven Eckelmann Signed-off-by: Simon Wunderlich

batman-adv: remove network coding support

2025-09-05T13:11:00Z

The Network Coding feature, introduced in 2013, is based on the master thesis "Inter-Flow Network Coding for Wireless Mesh Networks". It relies on the assumption that neighboring mesh nodes can reliably overhear each other's transmissions in promiscuous mode, allowing packets to be combined to reduce forwarding overhead. This assumption no longer holds for modern wireless mesh networks, which are heterogeneous and make overhearing increasingly unreliable. Factors such as multiple spatial streams, varying data rates, beamforming, and OFDMA all prevent nodes from consistently overhearing each other. The current implementation in batman-adv is not able to detect these conditions and would require a more complex layer beyond its neighbor discovery process to do so. In addition, the feature has been unmaintained for years and is discouraged for use. None of the current maintainers have the required test setup to verify its functionality, and known issues remain in its data structures (reference counting, RCU usage, and cleanup handling). Its continued presence also blocks necessary refactoring of the core originator infrastructure. Remove this obsolete and unmaintained feature. Signed-off-by: Sven Eckelmann Acked-by: Martin Hundebøll Acked-by: Marek Lindner Signed-off-by: Simon Wunderlich

batman-adv: store hard_iface as iflink private data

2025-05-31T08:41:11Z

By passing the hard_iface to netdev_master_upper_dev_link() as private data, we can iterate over hardifs of a mesh interface more efficiently using netdev_for_each_lower_private*() (instead of iterating over the global hardif list). In addition, this will enable resolving a hardif from its netdev using netdev_lower_dev_get_private() and getting rid of the global list altogether in the following patches. A similar approach can be seen in the bonding driver. Signed-off-by: Matthias Schiffer Signed-off-by: Sven Eckelmann Signed-off-by: Simon Wunderlich

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2025-03-20T20:38:01Z

Cross-merge networking fixes after downstream PR (net-6.14-rc8). Conflict: tools/testing/selftests/net/Makefile 03544faad761 ("selftest: net: add proc_net_pktgen") 3ed61b8938c6 ("selftests: net: test for lwtunnel dst ref loops") tools/testing/selftests/net/config: 85cb3711acb8 ("selftests: net: Add test cases for link and peer netns") 3ed61b8938c6 ("selftests: net: test for lwtunnel dst ref loops") Adjacent commits: tools/testing/selftests/net/Makefile c935af429ec2 ("selftests: net: add support for testing SO_RCVMARK and SO_RCVPRIORITY") 355d940f4d5a ("Revert "selftests: Add IPv6 link-local address generation tests for GRE devices."") Signed-off-by: Paolo Abeni

batman-adv: Limit aggregation size to outgoing MTU

2025-02-22T10:36:26Z

If a B.A.T.M.A.N. IV aggregated OGM was prepared, it was always assumed that 512 bytes (BATADV_MAX_AGGREGATION_BYTES) can be transmitted. But the outgoing MTU might be too small for these 512 bytes and the aggregation size must be adjusted in this case. Otherwise, the aggregates will cause unnecessary packet loss. For now, the non-aggregated packet length is not touched. Signed-off-by: Sven Eckelmann Signed-off-by: Simon Wunderlich

batman-adv: Use actual packet count for aggregated packets

2025-02-22T10:36:25Z

The batadv_forw_packet->num_packets didn't store the number of packets but the the number of packets - 1. This didn't had any effects on the actual handling of aggregates but can easily be a source of confusion when reading the code. Signed-off-by: Sven Eckelmann Signed-off-by: Simon Wunderlich

batman-adv: Switch to bitmap helper for aggregation handling

2025-02-22T10:36:25Z

The aggregation code duplicates code which already exists in the the bitops and bitmap helper. By switching to the bitmap helpers, operating on larger aggregations becomes possible without touching the different portions of the code which read/modify direct_link_flags. Signed-off-by: Sven Eckelmann Signed-off-by: Simon Wunderlich

batman-adv: Limit number of aggregated packets directly

2025-02-22T10:36:25Z

The currently selected size in BATADV_MAX_AGGREGATION_BYTES (512) is chosen such that the number of possible aggregated packets is lower than 32. This number must be limited so that the type of batadv_forw_packet->direct_link_flags has enough bits to represent each packet (with the size of at least 24 bytes). This requirement is better implemented in code instead of having it inside a comment. Signed-off-by: Sven Eckelmann Signed-off-by: Simon Wunderlich

batman-adv: Use consistent name for mesh interface

2025-02-22T10:36:22Z

The way how the virtual interface is called inside the batman-adv source code is not consistent. The genl headers call it meshif and the rest of the code calls is (mostly) softif. The genl definitions cannot be touched because they are part of the UAPI. But the rest of the batman-adv code can be touched to have a consistent name again. The bulk of the renaming was done using sed -i -e 's/soft\(-\|\_\| \|\)i\([nf]\)/mesh\1i\2/g' \ -e 's/SOFT\(-\|\_\| \|\)I\([NF]\)/MESH\1I\2/g' and then it was adjusted slightly when proofreading the changes. Signed-off-by: Sven Eckelmann Signed-off-by: Simon Wunderlich

batman-adv: Ignore own maximum aggregation size during RX

2025-02-08T18:24:33Z

An OGMv1 and OGMv2 packet receive processing were not only limited by the number of bytes in the received packet but also by the nodes maximum aggregation packet size limit. But this limit is relevant for TX and not for RX. It must not be enforced by batadv_(i)v_ogm_aggr_packet to avoid loss of information in case of a different limit for sender and receiver. This has a minor side effect for B.A.T.M.A.N. IV because the batadv_iv_ogm_aggr_packet is also used for the preprocessing for the TX. But since the aggregation code itself will not allow more than BATADV_MAX_AGGREGATION_BYTES bytes, this check was never triggering (in this context) prior of removing it. Cc: stable@vger.kernel.org Fixes: c6c8fea29769 ("net: Add batman-adv meshing protocol") Fixes: 9323158ef9f4 ("batman-adv: OGMv2 - implement originators logic") Signed-off-by: Sven Eckelmann Signed-off-by: Simon Wunderlich