The following commit has been merged in the batadv/net-next branch: commit ae63123e057993607de1617c2aec7ecdb6fbab1f Author: Sven Eckelmann sven@narfation.org Date: Sun Feb 2 12:39:57 2025 +0100

batman-adv: Add support for jumbo frames

Since batman-adv is not actually depending on hardware capabilities, it has no limit on the MTU. Only the lower hard interfaces can limit it. In case these have an high enough MTU or fragmentation is enabled, a higher MTU than 1500 can be enabled.

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

diff --git a/net/batman-adv/hard-interface.c b/net/batman-adv/hard-interface.c index 71b2236c00587..e7e7f14da03c9 100644 --- a/net/batman-adv/hard-interface.c +++ b/net/batman-adv/hard-interface.c @@ -618,10 +618,8 @@ out:

/* the real soft-interface MTU is computed by removing the payload * overhead from the maximum amount of bytes that was just computed. - * - * However batman-adv does not support MTUs bigger than ETH_DATA_LEN */ - return min_t(int, min_mtu - batadv_max_header_len(), ETH_DATA_LEN); + return min_t(int, min_mtu - batadv_max_header_len(), BATADV_MAX_MTU); }

/** diff --git a/net/batman-adv/main.h b/net/batman-adv/main.h index 626618d0c366e..4ecc304eaddd7 100644 --- a/net/batman-adv/main.h +++ b/net/batman-adv/main.h @@ -22,6 +22,8 @@ #define BATADV_THROUGHPUT_MAX_VALUE 0xFFFFFFFF #define BATADV_JITTER 20

+#define BATADV_MAX_MTU (ETH_MAX_MTU - batadv_max_header_len()) + /* Time To Live of broadcast messages */ #define BATADV_TTL 50

diff --git a/net/batman-adv/soft-interface.c b/net/batman-adv/soft-interface.c index 822d788a5f86b..301905672bb0b 100644 --- a/net/batman-adv/soft-interface.c +++ b/net/batman-adv/soft-interface.c @@ -790,7 +790,7 @@ static int batadv_softif_init_late(struct net_device *dev) atomic_set(&bat_priv->log_level, 0); #endif atomic_set(&bat_priv->fragmentation, 1); - atomic_set(&bat_priv->packet_size_max, ETH_DATA_LEN); + atomic_set(&bat_priv->packet_size_max, BATADV_MAX_MTU); atomic_set(&bat_priv->bcast_queue_left, BATADV_BCAST_QUEUE_LEN); atomic_set(&bat_priv->batman_queue_left, BATADV_BATMAN_QUEUE_LEN);

@@ -1043,6 +1043,7 @@ static void batadv_softif_init_early(struct net_device *dev) * have not been initialized yet */ dev->mtu = ETH_DATA_LEN; + dev->max_mtu = BATADV_MAX_MTU;

/* generate random address */ eth_hw_addr_random(dev);