shadowsocks client as transparent proxy, C implementation

SYNOPSIS

ss-redir [options]

DESCRIPTION

shadowsocks-c is a lightweight and secure socks5 proxy. It is a port of the original shadowsocks created by clowwindy. shadowsocks-c is written in pure C and takes advantage of libuv to achieve both high performance and low resource consumption.

shadowsocks-c consists of five components. ss-redir(1) works as a transparent proxy on local machines to proxy TCP traffic and requires netfilter's NAT module. For more information, check out shadowsocks-libev(8) and the following EXAMPLE section.

OPTIONS

Options include all supported platform variants; restrictions are noted below.

-f <pid_file>: Start shadowsocks as a daemon with specific pid file.

-s <server_host>: Set the server's hostname or IP.

-p <server_port>: Set the server's port number.

-l <local_port>: Set the local port number.

-k <password>: Set the password. The server and the client should use the same password.

-t <timeout>: Set the socket timeout in seconds. The default value is 60.

-m <encrypt_method>: Set the cipher. The default is chacha20-ietf-poly1305.

AEAD cipher names from the source (availability depends on the build):

    "aes-128-gcm",
    "aes-192-gcm",
    "aes-256-gcm",
    "2022-blake3-aes-128-gcm",
    "2022-blake3-aes-256-gcm",
    "chacha20-ietf-poly1305",
    "2022-blake3-chacha20-poly1305",
#ifdef FS_HAVE_XCHACHA20IETF
    "xchacha20-ietf-poly1305"
#endif

Legacy stream cipher names recognized by the source (disabled in minimal builds; some require backend support):

    "table",
    "rc4",
    "rc4-md5",
    "aes-128-cfb",
    "aes-192-cfb",
    "aes-256-cfb",
    "aes-128-ctr",
    "aes-192-ctr",
    "aes-256-ctr",
    "bf-cfb",
    "camellia-128-cfb",
    "camellia-192-cfb",
    "camellia-256-cfb",
    "cast5-cfb",
    "des-cfb",
    "idea-cfb",
    "rc2-cfb",
    "seed-cfb",
    "salsa20",
    "chacha20",
    "chacha20-ietf"

The 2022-blake3-* ciphers implement Shadowsocks 2022 (SIP022). They require a base64-encoded pre-shared key supplied with -k: 16 bytes for 2022-blake3-aes-128-gcm and 32 bytes for the other 2022 ciphers. Generate a 32-byte key with openssl rand -base64 32. Passwords are not stretched into keys for these ciphers.

-c <config_file>: Use a configuration file.

Refer to shadowsocks-c(8) CONFIG FILE section for more details.

-b <local_address>: Specify the local address to use while this client is making outbound connections to the server.

-a <user_name>: Run as a specific user.

-n <number>: Specify the maximum number of open files. Requires a platform with setrlimit support.

-h: Print help message.

-u: Enable UDP relay. Requires Linux TPROXY support and permission to configure transparent proxying.

-U: Enable UDP relay and disable TCP relay.

-T: Use TPROXY instead of REDIRECT for TCP traffic. Requires Linux TPROXY support.

-v: Enable verbose mode.

-6: Resolve hostname to IPv6 address first.

-A: Deprecated one-time authentication option. Exits with an error; use AEAD ciphers instead.

--fast-open: Enable TCP Fast Open where supported by the operating system.

--mtu <MTU>: Specify the MTU of your network interface.

--mptcp: Enable Multipath TCP.

Only available with MPTCP enabled Linux kernel.

--plugin <plugin_name>: Enable SIP003 plugin. (Experimental)

--plugin-opts <plugin_options>: Set SIP003 plugin options. (Experimental)

--reuse-port: Enable port reuse where supported by the operating system.

--tcp-incoming-sndbuf <size>: Set TCP send buffer size for incoming connections.

--tcp-incoming-rcvbuf <size>: Set TCP receive buffer size for incoming connections.

--tcp-outgoing-sndbuf <size>: Set TCP send buffer size for outgoing connections.

--tcp-outgoing-rcvbuf <size>: Set TCP receive buffer size for outgoing connections.

--no-delay: Enable TCP_NODELAY.

--password <password>: Set the password. The server and the client should use the same password.

--key <key_in_base64>: Set the key directly. The key should be encoded with URL-safe Base64.

--help: Print help message.

EXAMPLE

ss-redir requires netfilter's NAT function. Here is an example:

# Create new chain
iptables -t nat -N SHADOWSOCKS
iptables -t mangle -N SHADOWSOCKS
 
# Ignore your shadowsocks server's addresses
# It's very IMPORTANT, just be careful.
iptables -t nat -A SHADOWSOCKS -d 123.123.123.123 -j RETURN
 
# Ignore LANs and any other addresses you'd like to bypass the proxy
# See Wikipedia and RFC5735 for full list of reserved networks.
# See ashi009/bestroutetb for a highly optimized CHN route list.
iptables -t nat -A SHADOWSOCKS -d 0.0.0.0/8 -j RETURN
iptables -t nat -A SHADOWSOCKS -d 10.0.0.0/8 -j RETURN
iptables -t nat -A SHADOWSOCKS -d 127.0.0.0/8 -j RETURN
iptables -t nat -A SHADOWSOCKS -d 169.254.0.0/16 -j RETURN
iptables -t nat -A SHADOWSOCKS -d 172.16.0.0/12 -j RETURN
iptables -t nat -A SHADOWSOCKS -d 192.168.0.0/16 -j RETURN
iptables -t nat -A SHADOWSOCKS -d 224.0.0.0/4 -j RETURN
iptables -t nat -A SHADOWSOCKS -d 240.0.0.0/4 -j RETURN
 
# Anything else should be redirected to shadowsocks's local port
iptables -t nat -A SHADOWSOCKS -p tcp -j REDIRECT --to-ports 12345
 
# Add any UDP rules
ip route add local default dev lo table 100
ip rule add fwmark 1 lookup 100
iptables -t mangle -A SHADOWSOCKS -p udp --dport 53 -j TPROXY --on-port 12345 --tproxy-mark 0x01/0x01
 
# Apply the rules
iptables -t nat -A PREROUTING -p tcp -j SHADOWSOCKS
iptables -t mangle -A PREROUTING -j SHADOWSOCKS
 
# Start the shadowsocks-redir
ss-redir -u -c /etc/config/shadowsocks.json -f /var/run/shadowsocks.pid

SYNOPSIS

DESCRIPTION

OPTIONS

EXAMPLE

SEE ALSO