• Dave Watson's avatar
    tls: RX path for ktls · c46234eb
    Dave Watson authored
    Add rx path for tls software implementation.
    
    recvmsg, splice_read, and poll implemented.
    
    An additional sockopt TLS_RX is added, with the same interface as
    TLS_TX.  Either TLX_RX or TLX_TX may be provided separately, or
    together (with two different setsockopt calls with appropriate keys).
    
    Control messages are passed via CMSG in a similar way to transmit.
    If no cmsg buffer is passed, then only application data records
    will be passed to userspace, and EIO is returned for other types of
    alerts.
    
    EBADMSG is passed for decryption errors, and EMSGSIZE is passed for
    framing too big, and EBADMSG for framing too small (matching openssl
    semantics). EINVAL is returned for TLS versions that do not match the
    original setsockopt call.  All are unrecoverable.
    
    strparser is used to parse TLS framing.   Decryption is done directly
    in to userspace buffers if they are large enough to support it, otherwise
    sk_cow_data is called (similar to ipsec), and buffers are decrypted in
    place and copied.  splice_read always decrypts in place, since no
    buffers are provided to decrypt in to.
    
    sk_poll is overridden, and only returns POLLIN if a full TLS message is
    received.  Otherwise we wait for strparser to finish reading a full frame.
    Actual decryption is only done during recvmsg or splice_read calls.
    Signed-off-by: default avatarDave Watson <davejwatson@fb.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    c46234eb
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