matsumotory / tcp_save_syn_listen

listen() with TCP_SAVE_SYN using LD_PRELOAD

tcp_save_syn_listen

Change sys_listen() to listen() with TCP_SAVE_SYN using LD_PRELOAD

Build

make

Usage

LD_PRELOAD=src/tcp_save_syn_listen.so ./your_app

Example

cd test
make
# server don't use TCP_SAVE_SYN
./server

• other terminal

cd test
./client

• result

./server
tcpriv[info]: waiting...
tcpriv[info]: connected: 192.168.0.2
tcpriv[info]: syn_len: 0
server: server.c:112: read_saved_syn: Assertion `syn_len == 60' failed.
Aborted (core dumped)

However, if you use tcp_save_syn_listen, ./server's listen() set TCP_SAVE_SYN to socket automatically

LD_PRELOAD=./tcp_save_syn_listen/src/tcp_save_syn_listen.so ./server
tcpriv[info]: waiting...
tcpriv[info]: connected: 192.168.0.2
tcpriv[info]: syn_len: 60
tcpriv[info]: found tcpriv's information: kind=254 length=10 ExID=0xf991 uid=1000
tcpriv[info]: all test success.