From 29940ce32a2da2f3857d5fc459c6df6e47adb67e Mon Sep 17 00:00:00 2001 From: Vladimir Oltean Date: Wed, 16 Feb 2022 16:30:14 +0200 Subject: net: dsa: tag_ocelot_8021q: calculate TX checksum in software for deferred packets DSA inherits NETIF_F_CSUM_MASK from master->vlan_features, and the expectation is that TX checksumming is offloaded and not done in software. Normally the DSA master takes care of this, but packets handled by ocelot_defer_xmit() are a very special exception, because they are actually injected into the switch through register-based MMIO. So the DSA master is not involved at all for these packets => no one calculates the checksum. This allows PTP over UDP to work using the ocelot-8021q tagging protocol. Signed-off-by: Vladimir Oltean Signed-off-by: David S. Miller --- net/dsa/tag_ocelot_8021q.c | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'net/dsa/tag_ocelot_8021q.c') diff --git a/net/dsa/tag_ocelot_8021q.c b/net/dsa/tag_ocelot_8021q.c index 68982b2789a5..bd6f1d0e5372 100644 --- a/net/dsa/tag_ocelot_8021q.c +++ b/net/dsa/tag_ocelot_8021q.c @@ -32,6 +32,13 @@ static struct sk_buff *ocelot_defer_xmit(struct dsa_port *dp, if (!xmit_work_fn || !xmit_worker) return NULL; + /* PTP over IP packets need UDP checksumming. We may have inherited + * NETIF_F_HW_CSUM from the DSA master, but these packets are not sent + * through the DSA master, so calculate the checksum here. + */ + if (skb->ip_summed == CHECKSUM_PARTIAL && skb_checksum_help(skb)) + return NULL; + xmit_work = kzalloc(sizeof(*xmit_work), GFP_ATOMIC); if (!xmit_work) return NULL; -- cgit v1.2.3