From ae0b04b238e283cafd906cdc3489cf5dc9a825cf Mon Sep 17 00:00:00 2001 From: Tariq Toukan Date: Sun, 13 Dec 2020 16:39:29 +0200 Subject: [PATCH] net: Disable NETIF_F_HW_TLS_TX when HW_CSUM is disabled With NETIF_F_HW_TLS_TX packets are encrypted in HW. This cannot be logically done when HW_CSUM offload is off. Fixes: 2342a8512a1e ("net: Add TLS TX offload features") Signed-off-by: Tariq Toukan Reviewed-by: Boris Pismenny Link: https://lore.kernel.org/r/20201213143929.26253-1-tariqt@nvidia.com Signed-off-by: Jakub Kicinski --- Documentation/networking/tls-offload.rst | 8 +++++++- net/core/dev.c | 5 +++++ 2 files changed, 12 insertions(+), 1 deletion(-) diff --git a/Documentation/networking/tls-offload.rst b/Documentation/networking/tls-offload.rst index 37773da2bee5..0f55c6d540f9 100644 --- a/Documentation/networking/tls-offload.rst +++ b/Documentation/networking/tls-offload.rst @@ -524,7 +524,13 @@ on TCP retransmissions to handle corner cases is not acceptable. TLS device features ------------------- -Drivers should ignore the changes to TLS the device feature flags. +Drivers should ignore the changes to the TLS device feature flags. These flags will be acted upon accordingly by the core ``ktls`` code. TLS device feature flags only control adding of new TLS connection offloads, old connections will remain active after flags are cleared. + +TLS encryption cannot be offloaded to devices without checksum calculation +offload. Hence, TLS TX device feature flag requires NETIF_F_HW_CSUM being set. +Disabling the latter implies clearing the former. Disabling TX checksum offload +should not affect old connections, and drivers should make sure checksum +calculation does not break for them. diff --git a/net/core/dev.c b/net/core/dev.c index bde98cfd166f..0fd0d4eb678c 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -9643,6 +9643,11 @@ static netdev_features_t netdev_fix_features(struct net_device *dev, } } + if ((features & NETIF_F_HW_TLS_TX) && !(features & NETIF_F_HW_CSUM)) { + netdev_dbg(dev, "Dropping TLS TX HW offload feature since no CSUM feature.\n"); + features &= ~NETIF_F_HW_TLS_TX; + } + return features; }