flags and things
This is a list of possible flags you might include in telrc to provide various features for different types of devices.
banner
The banner flag is a global flag that is used to load a profile if it's seen during the login of a device. It allows regular expressions.
I needed a way to detect some devices when I connect to them. Normally we use regex on the hostname to see if it's a switch and use the switch profile, but in some cases there may be quirks from one switch vendor, so rather than overriding everything, or trying to detect the device type after login, we use hints from the devices telnet banner to determine what it is and load it's profile.
Example: Dlink doesn't use the normal backspace, it uses \b. We check for a banner screen that says DES-3(\d\d\d) and load the dlink profile when we see it.
hostname
Hostname is a router directive. It has two uses which are outlined below.
hostname (aliases)
Sometimes you want to connect to a device with a hostname that isn't in DNS. Maybe the DNS name is long and you want to abbreviate it, or maybe you want to set options, like username or login method when you connect on one name, then use different options on another name. You can do this with the hostname directive.
You can also use this to provide a port in the case that
{ 'regex' => '^gw1-dinglehopper', 'hostname' => 'shiny' },
hostname (CODE ref)
In very rare cases, you may want to take the hostname and rewrite it for some reason. If you need to do this you can pass an anonymous subroutine as the hostname and tel will run it with the original hostname as the argument. The return value should be the new hostname.
My use case for this is probably unique so I won't mention it, but as an example, let's say you wanted to take anything that started with C15 and replace it with a circuit ID from your database:
{ 'regex' => '^c15', 'hostname' => sub { use DBLookup qw (circuitid); return curcuitid($_[0]); } }
Even this is unrealistic, but I can't think of something generic to show right now.
handlers
This is a rtr or profile directive. It's used to override a key sequence. It takes a key or key combination and a function reference for arguments.
Syntax:
handlers => { 'key' => &function, 'another key' => &function2 },
I pass a reference to the $session handler as argument one.
As an example, if you wanted f5 to run a "sh ver" on cisco routers you could do this:
handlers => { '\[15~' => sub { ${$_[0]}->send("sh ver\r"); return 1; } }
The return 1; is required if you want the session to continue after the handler is run. So if you wanted to exit the router on f12 you could return 0;
port
Router or profile directive to indicate what port to connect on.
autocmds
Router or profile directive to run commands automatically when logging in. This is an array reference so it requires the square brackets surrounding the arguments.
Example:
'autocmds' => [ 'sh ver', 'sh ip int br' ],
hostsearch
This is a profile or router directive.
Arguments: routername Returns: a new routername
Usage: this is just like hostname in that it modifies the name during the connection stage. The difference here is that it tries to connect using the supplied name first, assuming that DNS will be available and such.
If the connection fails it calls your user supplied routine, which can, depending on how you write it, do a database lookup, a fuzzy match on the name, or any other modification.
In my case, some of our commercial devices use a prefix of "c-" to designate them, but we don't always type it when we're making a connection. So we have an alias like this:
'hostsearch' => sub { "c-$_[0]"; }
password
If a password is blank in the config file then the script will attempt to use a Keyring for authentication. It uses the Passwd::Keyring::Auto module for this if it's installed. If the password isn't found it will prompt you for it and store it in the keyring.
We also support retrieving the password from KeePass if the File::KeePass module is available.
keepass file
If you set this argument to a file then it will attempt to read the password from keepass.
keepass_file => $ENV{HOME} . "/keepass.kdbx",
keepass title
Setting keepass title tells it where to lookup the password in the file. If this is needed but not set we exit with a warning.
keepass_title => 'my router password',
keepass masterpwd
I don't advise you to store your keepass password anywhere in plaintext, but if you want to pass it to the script in an environment variable then you can specify it here
keepass_masterpwd => $ENV{KEEPASSPASSWORD},
Alternatively, I'm not sure how it'll work yet but maybe we could get the keepass password from a keyring lookup, or cache it in some other way.
syntax (not yet implemented)
If you want to load a syntax highlight module then you can specify the prefix here. For example, DlinkColor.pm would be loaded by
syntax => 'Dlink',
I would like to be able to chain these so that you can load more than one. That way you can have a default set of highlight rules for your company and a specific set of rules for Cisco routers or switches or whatever.
username_prompt and password_prompt
username_prompt => "nom d'utilisateur:",
password_prompt => 'mot de passe:',
You might have a system that has a prompt that isn't like one of the standard ones used by most vendors. You might even find systems that have been regionalized and prompt you in your native language. If this is the case you can override the default username and password prompts.
ena_username_prompt and ena_password_prompt
ena_username_prompt => "nom d'utilisateur:",
ena_password_prompt => 'mot de passe:',
Very similar to the normal username prompt. If your enable prompt has been changed to something you can override it using these commands.
pagercmd
pagercmd => 'disable clipaging',
Extreme networks and Dlink both use 'disable clipaging' while Cisco uses 'term length 0'. Juniper uses 'set cli screen-length 0', but also might need 'set cli complete-on-space off' to avoid annoying you while running scripts.
Some vendors don't have a command to turn off the pager. In those cases I tried setting tty rows to 10000. Not suprisingly, the vendors that I tried it on don't use the actual terminal size to control paging, so they still had more prompts every 20 or so lines.
If your particular device does respect tty sizing, and you have the Term::ReadKey module, then you can set:
pagercmd => sub { _stty_rows(10000) },
In any case, these pagercmds take effect when tel is run in a non-interactive mode, using either the -c or -x flags to specify scripts to run.
wishlist
- scrollback buffer across multiple sessions