OpenVPN中比较有用的一些脚本

这些脚本在很多情况下可以用到

主要是从openvpn的man中cp出来的

SCRIPTING AND ENVIRONMENTAL VARIABLES

OpenVPN exports a series of environmental variables for use by user-defined scripts.

Script Order of Execution

--up

Executed after TCP/UDP socket bind and TUN/TAP open.

--tls-verify

Executed when we have a still untrusted remote peer.

--ipchange

Executed after connection authentication, or remote IP address change.

--client-connect

Executed in --mode server mode immediately after client authentication.

--route-up

Executed after connection authentication, either immediately after, or some number of seconds after as defined by the --route-delay option.

--client-disconnect

Executed in --mode server mode on client instance shutdown.

--down

Executed after TCP/UDP and TUN/TAP close.

--learn-address

Executed in --mode server mode whenever an IPv4 address/route or MAC address is added to OpenVPN's internal routing table.

--auth-user-pass-verify

Executed in --mode server mode on new client connections, when the client is still untrusted.

String Types and Remapping

In certain cases, OpenVPN will perform remapping of characters in strings. Essentially, any characters outside the set of permitted characters for each string type will be converted to underbar ('_').

Q: Why is string remapping necessary?

A: It's an important security feature to prevent the malicious coding of strings from untrusted sources to be passed as parameters to scripts, saved in the environment, used as a common name, translated to a filename, etc.

Here is a brief rundown of OpenVPN's current string types and the permitted character class for each string:

X509 Names: Alphanumeric, underbar ('_'), dash ('-'), dot ('.'), at ('@'), colon (':'), slash ('/'), and equal ('='). Alphanumeric is defined as a character which will cause the C library isalnum() function to return true.

Common Names: Alphanumeric, underbar ('_'), dash ('-'), dot ('.'), and at ('@').

--auth-user-pass username: Same as Common Name.

--auth-user-pass password: Any "printable" character except CR or LF. Printable is defined to be a character which will cause the C library isprint() function to return true.

--client-config-dir filename as derived from common name or username: Alphanumeric, underbar ('_'), dash ('-'), and dot ('.') except for "." or ".." as standalone strings.

Environmental variable names: Alphanumeric or underbar ('_').

Environmental variable values: Any printable character.

For all cases, characters in a string which are not members of the legal character class for that string type will be remapped to underbar ('_').

Environmental Variables

Once set, a variable is persisted indefinitely until it is reset by a new value or a restart,

As of OpenVPN 2.0-beta12, in server mode, environmental variables set by OpenVPN are scoped according to the client objects they are associated with, so there should not be any issues with scripts having access to stale, previously set variables which refer to different client instances.

bytes_received

Total number of bytes received from client during VPN session. Set prior to execution of the --client-disconnect script.

bytes_sent

Total number of bytes sent to client during VPN session. Set prior to execution of the --client-disconnect script.

common_name

The X509 common name of an authenticated client. Set prior to execution of --client-connect, --client-disconnect, and --auth-user-pass-verify scripts.

config

Name of first --config file. Set on program initiation and reset on SIGHUP.

dev

The actual name of the TUN/TAP device, including a unit number if it exists. Set prior to --up or --down script execution.

foreign_option_

An option pushed via --push to a client which does not natively support it, such as --dhcp-option on a non-Windows system, will be recorded to this environmental variable sequence prior to --up script execution.

ifconfig_broadcast

The broadcast address for the virtual ethernet segment which is derived from the --ifconfig option when --dev tap is used. Set prior to OpenVPN calling the ifconfig or netsh (windows version of ifconfig) commands which normally occurs prior to --up script execution.

ifconfig_local

The local VPN endpoint IP address specified in the --ifconfig option (first parameter). Set prior to OpenVPN calling the ifconfig or netsh (windows version of ifconfig) commands which normally occurs prior to --up script execution.

ifconfig_remote

The remote VPN endpoint IP address specified in the --ifconfig option (second parameter) when --dev tun is used. Set prior to OpenVPN calling the ifconfig or netsh (windows version of ifconfig) commands which normally occurs prior to --up script execution.

ifconfig_netmask

The subnet mask of the virtual ethernet segment that is specified as the second parameter to --ifconfig when --dev tap is being used. Set prior to OpenVPN calling the ifconfig or netsh (windows version of ifconfig) commands which normally occurs prior to --up script execution.

ifconfig_pool_local_ip

The local virtual IP address for the TUN/TAP tunnel taken from an --ifconfig-push directive if specified, or otherwise from the ifconfig pool (controlled by the --ifconfig-pool config file directive). Only set for --dev tun tunnels. This option is set on the server prior to execution of the --client-connect and --client-disconnect scripts.

ifconfig_pool_netmask

The virtual IP netmask for the TUN/TAP tunnel taken from an --ifconfig-push directive if specified, or otherwise from the ifconfig pool (controlled by the --ifconfig-pool config file directive). Only set for --dev tap tunnels. This option is set on the server prior to execution of the --client-connect and --client-disconnect scripts.

ifconfig_pool_remote_ip

The remote virtual IP address for the TUN/TAP tunnel taken from an --ifconfig-push directive if specified, or otherwise from the ifconfig pool (controlled by the --ifconfig-pool config file directive). This option is set on the server prior to execution of the --client-connect and --client-disconnect scripts.

link_mtu

The maximum packet size (not including the IP header) of tunnel data in UDP tunnel transport mode. Set prior to --up or --down script execution.

local

The --local parameter. Set on program initiation and reset on SIGHUP.

local_port

The local port number, specified by --port or --lport. Set on program initiation and reset on SIGHUP.

password

The password provided by a connecting client. Set prior to --auth-user-pass-verify script execution only when the via-env modifier is specified, and deleted from the environment after the script returns.

proto

The --proto parameter. Set on program initiation and reset on SIGHUP.

remote_

The --remote parameter. Set on program initiation and reset on SIGHUP.

remote_port_

The remote port number, specified by --port or --rport. Set on program initiation and reset on SIGHUP.

route_net_gateway

The pre-existing default IP gateway in the system routing table. Set prior to --up script execution.

route_vpn_gateway

The default gateway used by --route options, as specified in either the --route-gateway option or the second parameter to --ifconfig when --dev tun is specified. Set prior to --up script execution.

route__

A set of variables which define each route to be added, and are set prior to --up script execution.

parm will be one of "network", "netmask", "gateway", or "metric".

n is the OpenVPN route number, starting from 1.

If the network or gateway are resolvable DNS names, their IP address translations will be recorded rather than their names as denoted on the command line or configuration file.

script_context

Set to "init" or "restart" prior to up/down script execution. For more information, see documentation for --up.

script_type

One of up, down, ipchange, route-up, tls-verify, auth-user-pass-verify, client-connect, client-disconnect, or learn-address. Set prior to execution of any script.

signal

The reason for exit or restart. Can be one of sigusr1, sighup, sigterm, sigint, inactive (controlled by --inactive option), ping-exit (controlled by --ping-exit option), ping-restart (controlled by --ping-restart option), connection-reset (triggered on TCP connection reset), error, or unknown (unknown signal). This variable is set just prior to down script execution.

tls_id_

A series of certificate fields from the remote peer, where n is the verification level. Only set for TLS connections. Set prior to execution of --tls-verify script.

tls_serial_

The serial number of the certificate from the remote peer, where n is the verification level. Only set for TLS connections. Set prior to execution of --tls-verify script.

tun_mtu

The MTU of the TUN/TAP device. Set prior to --up or --down script execution.

trusted_ip

Actual IP address of connecting client or peer which has been authenticated. Set prior to execution of --ipchange, --client-connect, and --client-disconnect scripts.

trusted_port

Actual port number of connecting client or peer which has been authenticated. Set prior to execution of --ipchange, --client-connect, and --client-disconnect scripts.

untrusted_ip

Actual IP address of connecting client or peer which has not been authenticated yet. Sometimes used to nmap the connecting host in a --tls-verify script to ensure it is firewalled properly. Set prior to execution of --tls-verify and --auth-user-pass-verify scripts.

untrusted_port

Actual port number of connecting client or peer which has not been authenticated yet. Set prior to execution of --tls-verify and --auth-user-pass-verify scripts.

username

The username provided by a connecting client. Set prior to --auth-user-pass-verify script execution only when the via-env modifier is specified.

SIGNALS

SIGHUP

Cause OpenVPN to close all TUN/TAP and network connections, restart, re-read the configuration file (if any), and reopen TUN/TAP and network connections.

SIGUSR1

Like SIGHUP, except don't re-read configuration file, and possibly don't close and reopen TUN/TAP device, re-read key files, preserve local IP address/port, or preserve most recently authenticated remote IP address/port based on --persist-tun, --persist-key, --persist-local-ip, and --persist-remote-ip options respectively (see above).

This signal may also be internally generated by a timeout condition, governed by the --ping-restart option.

This signal, when combined with --persist-remote-ip, may be sent when the underlying parameters of the host's network interface change such as when the host is a DHCP client and is assigned a new IP address. See --ipchange above for more information.

SIGUSR2

Causes OpenVPN to display its current statistics (to the syslog file if --daemon is used, or stdout otherwise).

SIGINT, SIGTERM

Causes OpenVPN to exit gracefully.