From 3983dc1674fec43beb8ce9d9bfdd6302fef86eae Mon Sep 17 00:00:00 2001 From: Andrew MacIntyre Date: Mon, 4 Nov 2024 22:41:25 +1100 Subject: [PATCH] vrx518_tc: allow larger MTU to support RFC4638 vrx518_tc currently sets the interface maximum MTU to the ethernet default of 1500 bytes by default via ether_setup() called from ptm_setup(). To support 1508 byte baby jumbo frames (RFC4638) for PPPoE connections over VDSL links as already supported by the VR9 ltq_ptm driver ([1], [2]) set the interface maximum MTU to MAX_MTU. MAX_MTU is defined in dcdp/inc/tc_common.h to 2002 bytes and this value is used in ptm_change_mtu() and elsewhere as the maximum MTU, however this is short circuited by checks against the interface maximum MTU. [1]: https://forum.openwrt.org/t/fritzbox-7530-and-rfc4638-baby-jumbo-frames/181327 [2]: https://git.openwrt.org/?p=openwrt/openwrt.git;a=commit;h=8a2a20e71e2909f84dab47e51dfda9e292a6c1ae Signed-off-by: Andrew MacIntyre --- dcdp/ptm_tc.c | 1 + 1 file changed, 1 insertion(+) --- a/dcdp/ptm_tc.c +++ b/dcdp/ptm_tc.c @@ -666,6 +666,7 @@ static void ptm_setup(struct net_device ether_setup(dev); dev->watchdog_timeo = 10 * HZ; dev->netdev_ops = &g_ptm_netdev_ops; + dev->max_mtu = MAX_MTU; } static int ptm_dev_init(struct tc_priv *tc_priv, u32 id,