(*

Module: Ssh

  Parses ssh client configuration

Author: Jiri Suchomel <jsuchome@suse.cz>

About: Reference

    ssh_config man page

About: License

    This file is licensed under the GPL.

About: Lens Usage

  Sample usage of this lens in augtool

(start code)

augtool> set /files/etc/ssh/ssh_config/Host example.com

augtool> set /files/etc/ssh/ssh_config/Host[.='example.com']/RemoteForward/machine1:1234 machine2:5678

augtool> set /files/etc/ssh/ssh_config/Host[.='example.com']/Ciphers/1 aes128-ctr

augtool> set /files/etc/ssh/ssh_config/Host[.='example.com']/Ciphers/2 aes192-ctr

(end code)

*)

module Ssh =

    autoload xfm

(************************************************************************

 * Group:                 USEFUL PRIMITIVES

 *************************************************************************)

    let eol = Util.doseol

    let spc = Util.del_ws_spc

    let spc_eq = del /[ \t]+|[ \t]*=[ \t]*/ " "

    let comment = Util.comment

    let empty = Util.empty

    let comma = Util.del_str ","

    let indent = Util.indent

    let value_to_eol = store Rx.space_in

    let value_to_spc = store /[^ \t\r\n=][^ \t\r\n]*/

    let value_to_comma = store /[^, \t\r\n=][^, \t\r\n]*/

(************************************************************************

 * Group:                 ENTRIES

 *************************************************************************)

    let array_entry (k:regexp) =

        [ indent . key k . counter "array_entry"

         . [ spc . seq "array_entry" . value_to_spc]* . eol ]

    let commas_entry (k:regexp) =

         let value = [ seq "commas_entry" . value_to_comma]

      in [ indent . key k . counter "commas_entry" . spc_eq .

           Build.opt_list value comma . eol ]

    let spaces_entry (k:regexp) =

         let value = [ seq "spaces_entry" . value_to_spc ]

      in [ indent . key k . counter "spaces_entry" . spc_eq .

           Build.opt_list value spc . eol ]

    let fw_entry (k:regexp) = [ indent . key k . spc_eq .

	    [ key /[^ \t\r\n\/=][^ \t\r\n\/]*/ . spc . value_to_eol . eol ]]

    let send_env = array_entry /SendEnv/i

    let proxy_command = [ indent . key /ProxyCommand/i . spc . value_to_eol . eol ]

    let remote_fw = fw_entry /RemoteForward/i

    let local_fw = fw_entry /LocalForward/i

    let ciphers = commas_entry /Ciphers/i

    let macs	= commas_entry /MACs/i

    let algorithms = commas_entry /(HostKey|Kex)Algorithms/i

    let pubkey_accepted_key_types = commas_entry /PubkeyAcceptedKeyTypes/i

    let global_knownhosts_file = spaces_entry /GlobalKnownHostsFile/i

    let rekey_limit = [ indent . key /RekeyLimit/i . spc_eq .

                        [ label "amount" . value_to_spc ] .

                        [ spc . label "duration" . value_to_spc ]? . eol ]

    let special_entry = send_env

	                    | proxy_command

	                    | remote_fw

	                    | local_fw

	                    | macs

	                    | ciphers

	                    | algorithms

	                    | pubkey_accepted_key_types

                        | global_knownhosts_file

                        | rekey_limit

    let key_re = /[A-Za-z0-9]+/

               - /SendEnv|Host|ProxyCommand|RemoteForward|LocalForward|MACs|Ciphers|(HostKey|Kex)Algorithms|PubkeyAcceptedKeyTypes|GlobalKnownHostsFile|RekeyLimit/i

    let other_entry = [ indent . key key_re

                    . spc_eq . value_to_spc . eol ]

    let entry = comment | empty

              | special_entry

	            | other_entry

    let host = [ key /Host/i . spc . value_to_eol . eol . entry* ]

(************************************************************************

 * Group:                 LENS

 *************************************************************************)

    let lns = entry* . host*

    let xfm = transform lns (incl "/etc/ssh/ssh_config" .

                             incl (Sys.getenv("HOME") . "/.ssh/config") .

                             incl "/etc/ssh/ssh_config.d/*.conf")