[tor-talk] Tor souce codes

[esolve esolve]

I'm doing research on Tor and I want to modify the tor exit node functions.

I downloaded the source codes from this link
https://gitweb.torproject.org/tor.git/tree/b13c6becc892d9716d8645f16b5d03bdb0b34651:/src

but I can't find the modules/files which are related to tor exit
functions(like receive cells from previous relay router, send HTTP/TCP
connection request to webserver/remote_host, buffer management)

can anyone give some hints? thanks!