cgroup2

Both cgroup and cgroup2 are enabled in linux by default. So you don't have to do anything about this.
- systemd-cgls to see the cgroup hierarchical tree.
- Why cgroup v2? Because simple, elegant and intuitive.
TPROXY

A process listening on port (e.g. 12345) to accept iptables TPROXY, for example v2ray's dokodemo-door in tproxy mode.

How to install

mkdir build && cd build && cmake .. && make && make install

It is alreay in archlinux AUR.
DEB and RPM are packaged in release page.

Default usage

First enable and start service

sudo systemctl enable --now cgproxy.service

Then prefix with cgproxy with your command, just like proxychains
```
cgproxy [--debug] <CMD>
```

For example, test proxy

cgproxy curl -vI https://www.google.com

To completely stop

sudo systemctl disable --now cgproxy.service

Configuration

Config file: /etc/cgproxy/config.json

{
    "cgroup_noproxy": ["/system.slice/v2ray.service"],
    "cgroup_proxy": [],
    "enable_dns": true,
    "enable_gateway": false,
    "enable_ipv4": true,
    "enable_ipv6": true,
    "enable_tcp": true,
    "enable_udp": true,
    "port": 12345
}

port tproxy listenning port
cgroup_noproxy cgroup array that no need to proxy, /noproxy.slice is preserved
cgroup_proxy cgroup array that need to proxy, /proxy.slice is preserved
enable_gateway enable gateway proxy for local devices
enable_dns enable dns to go to proxy
enable_tcp
enable_udp
enable_ipv4
enable_ipv6

Note: cgroup in configuration need to be exist, otherwise ignored

If you changed config, remember to restart service

sudo systemctl restart cgproxy.service

Global transparent proxy

Set "cgroup_proxy":["/"] in configuration, this will proxy all connection
Allow your proxy program (v2ray) direct to internet to avoid loop. Two ways:
- active way, run command
  
  example: cgnoproxy sudo v2ray -config config_file
  
  example: cgnoproxy qv2ray
- passive way, set it's cgroup in configuration, very useful for service
  
  example: "cgroup_noproxy":["/system.slice/v2ray.service"]
Finally, restart cgproxy service, that's all

Gateway proxy

Set "enable_gateway":true in configuration
And allow your proxy software (v2ray) direct to internet if necessary, described above
Other device set this host as gateway, and set public dns if need

Other useful tools provided in this project

cgnoproxy run program wihout proxy, very useful in global transparent proxy
```
cgnoproxy [--debug] <CMD> 
```
cgattach attach specific process pid to specific cgroup which will create if not exist , cgroup can be only one level down exist cgroup, otherwise created fail.

You need to set set(build_tools ON) in CmakeLists.txt to build this.
```
cgattch <pid> <cgroup>
# example
cgattch 9999 /proxy.slice
```

NOTES

v2ray TPROXY need root or special permission, use service or

sudo setcap "cap_net_admin,cap_net_bind_service=ep" /usr/lib/v2ray/v2ray

Why not outbound mark solution, because in v2ray when "localhost" is used, out-going DNS traffic is not controlled by V2Ray, so no mark at all, that's pity.

TIPS

systemd-cgls to see the cgroup hierarchical tree.
Check cgroup2 support findmnt -t cgroup2
Offer you v2ray service and full config exmaple in v2ray_config
Offer you qv2ray config example

Licences

cgproxy is licenced under