A shadowsocks SIP003 (SIP003u) Plugin with connection multiplexor in YAMUX protocol

ClientA ----+
            |  N Connections
ClientB ----+---- sslocal ---- yamux-plugin-local
            |                           |
ClientC ----+                           |
                                        | M (TCP) Connections
RemoteA ----+                           |
            |                           |
RemoteB ----+---- ssserver ---- yamux-plugin-server
            |  N Connections
RemoteC ----+

yamux-plugin could mulplex N TCP / UDP connections into M TCP tunnels, which N >= M.

cargo build --release

{
    "plugin_opts": "outbound_fwmark=100&outbound_user_cookie=100&outbound_bind_interface=eth1&outbound_bind_addr=1.2.3.4"
}

• outbound_fwmark: Linux (or Android) sockopt SO_MARK
• outbound_user_cookie: FreeBSD sockopt SO_USER_COOKIE
• outbound_bind_interface: Socket binds to interface, Linux SO_BINDTODEVICE, macOS IP_BOUND_IF, Windows IP_UNICAST_IF
• outbound_bind_addr: Socket binds to IP
• udp_timeout: UDP tunnel timeout (default 5 minutes)
• tcp_keep_alive: TCP socket keep-alive time (default 15 seconds)
• tcp_fast_open: TCP Fast Open
• mptcp: Multipath-TCP
• ipv6_first: Connect IPv6 first (default true)