From: Andrew MacIntyre Date: Fri, 8 Nov 2024 12:44:13 +0000 (+1100) Subject: vrx518_tc: allow larger MTU to support RFC4638 X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=ca53f2d430ce1f9ff5a560291de1e93380963417;p=openwrt%2Fopenwrt.git 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 Link: https://github.com/openwrt/openwrt/pull/16856 Signed-off-by: Robert Marko --- diff --git a/package/kernel/lantiq/vrx518_tc/patches/206-dcdp-ptm_tc-allow-larger-mtu-to-support-rfc4638.patch b/package/kernel/lantiq/vrx518_tc/patches/206-dcdp-ptm_tc-allow-larger-mtu-to-support-rfc4638.patch new file mode 100644 index 0000000000..35a709e9fa --- /dev/null +++ b/package/kernel/lantiq/vrx518_tc/patches/206-dcdp-ptm_tc-allow-larger-mtu-to-support-rfc4638.patch @@ -0,0 +1,34 @@ +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 2023-12-17 16:11:22.503500398 +1100 ++++ b/dcdp/ptm_tc.c 2024-01-26 16:48:49.881623474 +1100 +@@ -657,6 +657,7 @@ 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,