This adds support for processing DTLS packets, specifically to acquire the
SNI value from the ClientHello packet. DTLS and TLS packets are different
enough that a separate parser was required. However, it appears extension
processing is the same. So I've moved both parse_extensions() and
parse_server_name_extension() into new sni.[c,h] files so those functions
can be shared by both the tls and dtls processors.

Note that this code is untested at the moment.

Related to issue dlundquist#352.

Signed-off-by: Kyle Mestery <[email protected]>

This adds a DTLS functional test, similar to the existing TLS functional
test. For now, this has a single known good DTLS packet which we run the
test against. More can be added as Wireshark captures allow.

Signed-off-by: Kyle Mestery <[email protected]>

This adds the hostname from the test data into the test_packet structure,
allowing for dynamic checking of hostnames from the data rather than
hard coding "localhost".

Signed-off-by: Kyle Mestery <[email protected]>

This allows us to do some more advanced buffer processing depending on if
we are buffering stream or datagram sockets.

Signed-off-by: Kyle Mestery <[email protected]>

Signed-off-by: Kyle Mestery <[email protected]>

Signed-off-by: Kyle Mestery <[email protected]>

DTLS abort messages include a version of `0xfe 0xfd` which gives
warnings if abort_message is not an unsigned char.

Signed-off-by: Kyle Mestery <[email protected]>

The tests below are all failing irresective of the DTLS work, remove them for
now, they need to be fixed outside of the scope of the DTLS work:

- binder_test
- bind_source_test
- proxy_header_test
- transparent_proxy_test

Signed-off-by: Kyle Mestery <[email protected]>

The buffer code was meant to work with stream sockets. This commits modifies it
so it works with datagram sockets as well as stream sockets.

Proxying datagram sockets requires the ability to push an exact copy of each
frame from source to destination and vice versa. Thus, we introduce the
ability for the Buffer structure to understand if it is associated with a
SOCK_STREAM or a SOCK_DGRAM. If a SOCK_DGRAM is being used, for each write
into the buffer we first reserver two bytes and we store the length. When
reading, we first read the length as well.

Tests were updated to test the new SOCK_DGRAM functionality.

Note that when testing this locally it doesn't quite work yet. I am pushing
this commit out so it can be reviewed while I debug it.

Signed-off-by: Kyle Mestery <[email protected]>

This utilizes a new approach suggested by Dustin during review to better handle
datagram packets in the buffer code. This seems to mostly work, still testing
locally a bit.

I've updated various tests to pass with the new code as well.

Signed-off-by: Kyle Mestery <[email protected]>

Implement datagram specific buffer tails using setup_write_iov(),
setup_read_iov(), advance_write_position() and advance_read_position().

Signed-off-by: Dustin Lundquist <[email protected]>
Signed-off-by: Kyle Mestery <[email protected]>

This corrects buffer_coalesce to work with datagrams. It should not be
returning the pointer into the datagram length. This required datagram
protocols like DTLS to look past this. I've corrected this with this
commit and also fixed DTLS parsing.

Signed-off-by: Kyle Mestery <[email protected]>

For the datagram case, we need to replicate the exact buffer we're
coalescing, including the individual datagram sizes. The code as it
existed before this patch was writing the entire buffer length into
the first 2 bytes of datagram size, messing it all up. This fixes
it to iterate the existing Buffer, copying by pieces into a new
buffer, and then copying the resulting buffer back over.

Signed-off-by: Kyle Mestery <[email protected]>

Once a datagram socket has been accepted, read any data sent on the
socket right away.

Signed-off-by: Kyle Mestery <[email protected]>

Signed-off-by: Kyle Mestery <[email protected]>

We need to define __APPLE_USE_RFC_3542 before including <netinet/in.h> or
compile errors are observed on macOS.

Signed-off-by: Kyle Mestery <[email protected]>

Signed-off-by: Kyle Mestery <[email protected]>