teainside/teavpn2

TeaVPN2 - An open source VPN Software (currently supported platform is only Linux).

TeaVPN2

TeaVPN2 is an open source VPN Software. Current supported platform is only Linux. We plan to expand to other platforms (contributors are welcomed).

Build Requirements

• GNU Make 4.3
• gcc 9.3+ or clang 11+

Build

sudo apt-get install gcc clang make build-essential -y;
git clone https://github.com/TeaInside/teavpn2;
cd teavpn2;
make -j$(nproc);

For build with GUI support:

./configure --gui;
make -j$(nproc);

Issues

We welcome bug reports, feature requests and questions through GitHub repository https://github.com/TeaInside/teavpn2 (kindly to open an issue).

Project Maintainer

• Ammar Faizi (@ammarfaizi2)

Community

We are online on Telegram, see https://t.me/TeaInside

Contributing

We accept pull request on the GitHub repository.

License

This software is licensed under the GNU GPL-v2 license.

teavpn2's Issues

[TCP Server] Implement OpenSSL encryption

This will be merged to 0.1.0 and I am assigning this issue to myself.

An improper locking bug(e.g., deadlock) on the lock state->mutex

Hi, developers, thank you for your checking. It seems the lock state->mutex is not released correctly when unlikely(err != 0) in the function init_thread?

teavpn2/src/teavpn2/server/linux/tcp_mt.c

Lines 470 to 481 in d1a9999

	pthread_mutex_lock(&state->mutex);
	/* Give the lock to the thread */
	state->mutex_own = true;
	memset(&attr, 0, sizeof(attr));
	err = pthread_attr_init(&attr);
	if (unlikely(err != 0)) {
	err = (err < 0) ? -err : err;
	pr_err("pthread_attr_init: " PRERF, PREAR(err));
	return -1;
	}

[UDP] Having multiple clients at once makes the client sometimes freeze

I found that when the server is handling multiple connections at once, the VPN client sometimes freezes until it reaches timeout and closes everything.

I don't have more info about what is going on now. It seems we have a nasty session logic bug in the server side.

Stay tuned. I should figure out soon what is happening...

I am going to use this issue as a placeholder to add more info as I better understand what has broken with the current session handling.

[TCP server] Multithreading support

I am going to develop multithreading support for TCP server, it will yield massive breaking changes, so we will skip 0.0.1 and jump to 0.1.0.

Add TCP support

Create the makefile

Handle verbose level

Add verbose level for log output support.

teavpn2/src/teavpn2/server/argv.c

Lines 95 to 96 in e924c1b

	case 'v':
	break;

Multiple Clients

Need guide to contribute

Please guide the contributors how to contribute to this repository, start by explaining technical line about the program maybe?

Create client executable, argument parser and config parser.

Before we go to #2 and #3.
We should prepare the client first, so we can add TCP and UDP support to both (client and server).

TODO list for TeaVPN client:

1. Create argument parser.
2. Create config ini parser.
3. Create unit tests and codecov.

I found the data corruption culprit!

We have been testing TeaVPN2 and still can't achieve a stable connection state when the traffic is crowded. I suspected there is data corruption in the event loop. Today I found the problem, and it is indeed data corruption.

This data corruption will not be detected by Valgrind, because the read/write to memory is all done legally to the correct memory address. However, the read/write mechanism is not legal for the event loop.

Below is the explanation (image attached):

An improper locking bug(e.g., deadlock) on the lock client->mutex

Hi, developers, thank you for your checking. It seems the lock client->mutex is not released correctly when unlikely(!client->is_used) in the function destroy_state?

teavpn2/src/teavpn2/server/linux/tcp_mt.c

Lines 691 to 708 in d1a9999

	pthread_mutex_lock(&client->mutex);
	}
	if (unlikely(!client->is_used))
	goto clear;
	prl_notice(0, "Closing clients[%d].cli_fd (%d)",
	max_conn, client->cli_fd);
	close(client->cli_fd);
	if (likely(client->mt_act)) {
	pthread_mutex_unlock(&client->mutex);
	pthread_mutex_destroy(&client->mutex);
	}
	clear:
	memset(client, 0, sizeof(struct tcp_client));
	}

Add UDP support

Fix help output

ii64 <[email protected]> has got bad experience due to lack of help output
https://t.me/TeaInside/43726

Note for myself (Ammar):
Don't forget to fix the basic help. Next time when you ask someone to test your code, make sure everything is well prepared, so they don't get bad experience.

`ret` maybe uninitialized in `put_udp_session`

@ammarfaizi2, in commit 667576c ("udp_session.c: implement put_udp_session") you forgot to initialize the int ret. If state->sess_map is NULL, you will return an uninitialized value.

teavpn2/src/teavpn2/server/linux/udp_session.c

Lines 188 to 201 in 667576c

	int put_udp_session(struct srv_udp_state *state, struct udp_sess *cur_sess)
	__acquires(&state->sess_stk_lock)
	__releases(&state->sess_stk_lock)
	{
	int ret;
	mutex_lock(&state->sess_stk_lock);
	BUG_ON(bt_stack_push(&state->sess_stk, cur_sess->idx) == -1);
	if (state->sess_map)
	ret = remove_sess_from_bkt(state, cur_sess);
	reset_udp_session(cur_sess, cur_sess->idx);
	mutex_unlock(&state->sess_stk_lock);
	atomic_fetch_sub(&state->active_sess, 1);
	return ret;
	}