From 203ffc4ca75d43ac32b164c5a474e3ce36999809 Mon Sep 17 00:00:00 2001 From: Felix Fietkau Date: Fri, 6 May 2022 21:54:48 +0200 Subject: [PATCH] kernel: fix corrupted padding on small packets with mt753x dsa Signed-off-by: Felix Fietkau --- ...a-tag_mtk-add-padding-for-tx-packets.patch | 29 +++++++++++++++++++ ...a-tag_mtk-add-padding-for-tx-packets.patch | 29 +++++++++++++++++++ 2 files changed, 58 insertions(+) create mode 100644 target/linux/generic/pending-5.10/705-net-dsa-tag_mtk-add-padding-for-tx-packets.patch create mode 100644 target/linux/generic/pending-5.15/705-net-dsa-tag_mtk-add-padding-for-tx-packets.patch diff --git a/target/linux/generic/pending-5.10/705-net-dsa-tag_mtk-add-padding-for-tx-packets.patch b/target/linux/generic/pending-5.10/705-net-dsa-tag_mtk-add-padding-for-tx-packets.patch new file mode 100644 index 0000000000..e27ac3595f --- /dev/null +++ b/target/linux/generic/pending-5.10/705-net-dsa-tag_mtk-add-padding-for-tx-packets.patch @@ -0,0 +1,29 @@ +From: Felix Fietkau +Date: Fri, 6 May 2022 21:38:42 +0200 +Subject: [PATCH] net: dsa: tag_mtk: add padding for tx packets + +Padding for transmitted packets needs to account for the special tag. +With not enough padding, garbage bytes are inserted by the switch at the +end of small packets. + +Fixes: 5cd8985a1909 ("net-next: dsa: add Mediatek tag RX/TX handler") +Signed-off-by: Felix Fietkau +--- + +--- a/net/dsa/tag_mtk.c ++++ b/net/dsa/tag_mtk.c +@@ -25,6 +25,14 @@ static struct sk_buff *mtk_tag_xmit(stru + u8 xmit_tpid; + u8 *mtk_tag; + ++ /* The Ethernet switch we are interfaced with needs packets to be at ++ * least 64 bytes (including FCS) otherwise their padding might be ++ * corrupted. With tags enabled, we need to make sure that packets are ++ * at least 68 bytes (including FCS and tag). ++ */ ++ if (__skb_put_padto(skb, ETH_ZLEN + MTK_HDR_LEN, false)) ++ return NULL; ++ + /* Build the special tag after the MAC Source Address. If VLAN header + * is present, it's required that VLAN header and special tag is + * being combined. Only in this way we can allow the switch can parse diff --git a/target/linux/generic/pending-5.15/705-net-dsa-tag_mtk-add-padding-for-tx-packets.patch b/target/linux/generic/pending-5.15/705-net-dsa-tag_mtk-add-padding-for-tx-packets.patch new file mode 100644 index 0000000000..e27ac3595f --- /dev/null +++ b/target/linux/generic/pending-5.15/705-net-dsa-tag_mtk-add-padding-for-tx-packets.patch @@ -0,0 +1,29 @@ +From: Felix Fietkau +Date: Fri, 6 May 2022 21:38:42 +0200 +Subject: [PATCH] net: dsa: tag_mtk: add padding for tx packets + +Padding for transmitted packets needs to account for the special tag. +With not enough padding, garbage bytes are inserted by the switch at the +end of small packets. + +Fixes: 5cd8985a1909 ("net-next: dsa: add Mediatek tag RX/TX handler") +Signed-off-by: Felix Fietkau +--- + +--- a/net/dsa/tag_mtk.c ++++ b/net/dsa/tag_mtk.c +@@ -25,6 +25,14 @@ static struct sk_buff *mtk_tag_xmit(stru + u8 xmit_tpid; + u8 *mtk_tag; + ++ /* The Ethernet switch we are interfaced with needs packets to be at ++ * least 64 bytes (including FCS) otherwise their padding might be ++ * corrupted. With tags enabled, we need to make sure that packets are ++ * at least 68 bytes (including FCS and tag). ++ */ ++ if (__skb_put_padto(skb, ETH_ZLEN + MTK_HDR_LEN, false)) ++ return NULL; ++ + /* Build the special tag after the MAC Source Address. If VLAN header + * is present, it's required that VLAN header and special tag is + * being combined. Only in this way we can allow the switch can parse -- 2.30.2