Re: [tor-dev] [PATCH] torify/torsocks and TCP Fast Open

On Wed, 21 Jan 2015 15:26:56 -0500 David Goulet dgoulet@ev0ke.net wrote:

...

+/*

• • Using TCP Fast Open (TFO) uses sendto() instead of connect()

with 'flags'

• • set to MSG_FASTOPEN. Without this code, using TFO simply

bypasses TOR

• • without letting the user know.
• • This solution simply ignores TFO and falls back to connect().
• • At the time the TOR server supports TFO, socks5.c (client code)

could

• • implement it in send_data() and connect_socks5().

Could you simply clarify this for me meaning what's needed in socks5 code for TFO to be supported? (no need for an extra comments, just how would I do that :)

This doesn't really make sense when a proxy is in the picture. What would you include as the TFO payload? The "VER | NMETHODS | METHODS" SOCKS5 handshake?

In the vast majority of the deployed configurations, the client code talks to tor over a loopback interface, so cutting out 1xRTT isn't worth the added code (There's a case to be made for using TFO for inter-relay traffic, but that's entirely orthogonal to this.).

Regards,