Hello,

On 29.03.2017 19:41, David Miller wrote:

From: Aviad Yehezkel <redacted>
Date: Tue, 28 Mar 2017 16:26:17 +0300

quoted

TLS Tx crypto offload is a new feature of network devices. It
enables the kernel TLS socket to skip encryption and authentication
operations on the transmit side of the data path, delegating those
to the NIC. In turn, the NIC encrypts packets that belong to an
offloaded TLS socket on the fly. The NIC does not modify any packet
headers. It expects to receive fully framed TCP packets with TLS
records as payload. The NIC replaces plaintext with ciphertext and
fills the authentication tag. The NIC does not hold any state beyond
the context needed to encrypt the next expected packet,
i.e. expected TCP sequence number and crypto state.

It seems like, since you do the TLS framing in TCP and the card is
expecting to fill in certain aspects, there is a requirement that the
packet contents aren't mangled between the TLS framing code and when
the SKB hits the card.

Is this right?

For example, what happens if netfilter splits a TLS Tx offloaded frame
into two TCP segments?

Furthermore, it doesn't seem to work with bonding or any other virtual
interface, which could move the skb's to be processed on another NIC, as
the context is put onto the NIC. Even a redirect can not be processed
anymore (seems like those patches try to stick the connection to an
interface anyway).

Wouldn't it be possible to keep the state in software and push down a
security context per skb, which get applied during sending? If not
possible via hw, slowpath can encrypt packet in sw.

Also sticking connections to outgoing interfaces might work for TX, but
you can't force the interface where packets come in.

Bye,
Hannes