#!/bin/bash
# Copyright (c) 2004-2005 Gentoo Foundation
# Distributed under the terms of the GNU General Public License v2

# function rename wrapper - remove for baselayout-1.12.x
if [[ $( type -t bash_variable ) != "function" ]] ; then
    bash_variable() {
    interface_variable "$*"
    }
fi

# char* pppd_provides(void)
#
# Returns a string to change module definition for starting up
pppd_provides() {
    echo "ppp"
}

# void pppd_depend(void)
#
# Sets up the dependancies for the module
pppd_depend() {
    after interface
    before dhcp
}

# bool pppd_check_installed(void)
#
# Returns 1 if pppd is installed, otherwise 0
pppd_check_installed() {
    if [[ ! -x /usr/sbin/pppd ]]; then
    ${1:-false} && eerror "For PPP support, emerge net-dialup/ppp"
    return 1
    fi
    return 0
}

# bool pppd_check_depends(void)
#
# Checks to see if we have the needed functions
pppd_check_depends() {
    return 0
}

# char *pppd_regex_escape(char *string)
#
# Returns the supplied string with any special regex
# characters escaped so they don't provide regex intructions
# This may be a candidate for adding to /sbin/functions.sh or
# net-scripts functions at some point
pppd_regex_escape() {
    local regex="$*"
    regex="${regex//\\/\\\\}"
    regex="${regex//\*/\\*}"
    regex="${regex//[/\[}"
    regex="${regex//]/\]}"
    regex="${regex//./\.}"
    regex="${regex//\$/\\$}"
    regex="${regex//^/\^}"
    regex="${regex//(/\(}"
    regex="${regex//)/\)}"
    regex="${regex//\?/\\?}"
    regex="${regex//+/\+}"
    regex="${regex//{/\{}"
    regex="${regex//\}/\}}"
    echo "${regex}"
}

# bool pppd_update_secrets_file(char* filepath, char* username, \
#    char* remotename, char* password)
#
# Add/update PAP/CHAP authentication information 
pppd_update_secrets_file() {
    local file="$1" username="$2" remote="$3" password="$4"
    local tmpfile="/tmp/ppp-secret.$$"

    # Build an egrep to find a line in /etc/ppp/{pap,chap}-secrets
    local euser=$( pppd_regex_escape "${username}" )
    local epassword=$( pppd_regex_escape "${password}" )

    local regex='^[[:blank:]]*[\"]?'"${euser}"'[\"]?[[:blank:]]*'
    regex="${regex}"'[\"]?'"${remote}"'[\"]?[[:blank:]]*'

    # The find regex needs to search for a matching password too
    local find_regex="${regex}"'[\"]?'"${epassword}"'([\"[[:blank:]]]?|$)'

    # Don't update if the information is already there
    [[ -e ${file} ]] && egrep -q "${find_regex}" "${file}" && return 0

    # Create our tmp file with secure permissions
    touch "${tmpfile}" || return 1
    chmod 0600 "${tmpfile}" || return 1

    # Now dump the secrets file minus any current security info that
    # matches what we want to insert into our temporary file and move that back
    # to the secrets file. We do this because grep cannot read and write to
    # the same fd at the same time (which makes sense)
    [[ -e "${file}" ]] && egrep -v "${regex}" "${file}" > "${tmpfile}"

    # Escape the \ symbol in the username and password so that echo -e
    # does not expand it
    username="${username//\\/\\\\}"
    password="${password//\\/\\\\}"

    echo -e "\"${username}\"\t\"${remote}\"\t\"${password}\"" >> "${tmpfile}"
    vewarn "Authentication info has been added to ${file}"
    mv "${tmpfile}" "${file}" ||  return 1

    return 0
}

# bool pppd_start(char *iface)
#
# Start PPP on an interface by calling pppd
#
# Returns 0 (true) when successful, otherwise 1
pppd_start() {
    local iface="$1" ifvar=$( bash_variable "$1" ) opts="" link
    if [[ ${iface%%[0-9]*} != "ppp" ]]; then
        eerror "PPP can only be invoked from net.ppp[0-9]"
        return 1
    fi

    local unit="${iface#ppp}"
    if [[ -z ${unit} ]] ; then
        eerror "PPP requires a unit - use net.ppp[0-9] instead of net.ppp"
        return 1
    fi

    # PPP requires a link to communicate over - normally a serial port
    # PPPoE communicates over ethernet
    # PPPoA communictes over ATM
    # In all cases, the link needs to be available before we start PPP
    eval link=\"\$\{link_${ifvar}\}\"
        if [[ -z ${link} ]]; then
        eerror "link_${ifvar} has not been set in /etc/conf.d/net"
        return 1
    fi

    # Might or might not be set in conf.d/net
    local user password i
    eval username=\"\$\{username_${ifvar}\}\"
    eval password=\"\$\{password_${ifvar}\}\"

    #Add/update info in PAP/CHAP secrets files
    if [[ -n ${username} && -n ${password} ]]; then
        for i in chap pap ; do
            if ! pppd_update_secrets_file "/etc/ppp/${i}-secrets" \
                    "${username}" "${iface}" "${password}" ; then
                eerror "Failed to update /etc/ppp/${i}-secrets"
                return 1
            fi
        done
    fi

    # Load any commandline options
    eval opts=\"\$\{pppd_${ifvar}\[@\]}\"

    # We don't work if nodetach or unit is set
    for i in nodetach unit ; do
        if [[ " ${opts} " == *" ${i} "* ]]; then
            eerror "The option \"${i}\" is not allowed"
            return 1
        fi
    done

    # Check for mtu/mru
    local mtu
    eval mtu=\"\$\{mtu_${ifvar}\}\"
    if [[ -n ${mtu} ]]; then
        [[ " ${opts} " != *" mtu "* ]] && opts="${opts} mtu ${mtu}"
        [[ " ${opts} " != *" mru "* ]] && opts="${opts} mru ${mtu}"
    fi

    # Detach if we're not idling
    [[ " ${opts} " != *" idle "* && " ${opts} " != *" updetach "* ]] \
        && opts="${opts} updetach"

    # Setup auth info
    [[ -n ${username} ]] && opts="user ${username} ${opts}"
	opts="remotename ${iface} ${opts}"

    # Load a custom interface configuration file if it exists
    [[ -f "/etc/ppp/options.${iface}" ]] \
        && opts="${opts} file /etc/ppp/options.${iface}"

    # Set forced options
    opts="unit ${unit} persist maxfail 0 ${opts}"

    local -a plugins
    eval plugins=( \"\$\{plugins_${ifvar}\}\" )
    for (( i=0; i<${#plugins[@]}; i++ )); do
        local -a plugin=( ${plugins[i]} )
        # Bound to be some users who do this
        [[ ${plugin[0]} == "pppoe" ]] && plugin[0]="rp-pppoe"
        [[ ${plugin[0]} == "pppoa" ]] && plugin[0]="pppoatm"

        [[ ${plugin[0]} == "rp-pppoe" ]] && opts="${opts} connect true"
        opts="${opts} plugin ${plugin[0]}.so ${plugin[@]:1}"
        [[ ${plugin[0]} == "rp-pppoe" ]] && opts="${opts} ${link}"
    done

    if [[ " ${opts} " == *" plugin rp-pppoe.so "* ]]; then
        # Ensure that the link exists and is up
        interface_exists "${link}" true || return 1
        interface_up "${link}"

        # Load the pppoe kernel module - if this fails, we have to hope
        # that pppoe support is compiled into the kernel
        modprobe pppoe 2>/dev/null
    fi
    
    ebegin "Running pppd"
    i=$( /usr/sbin/pppd ${opts}  )
    eend $? "${i}" || return 1

    local addr=$( interface_get_address "${iface}" )
    einfo "${iface} received address ${addr}"
}

# bool pppd_stop(char *iface)
#
# Stop PPP link by killing the associated pppd process
#
# Returns 0 (true) if no process to kill or it terminates successfully,
# otherwise non-zero (false)
pppd_stop() {
    local iface="$1" pidfile="/var/run/$1.pid"

    [[ ! -s ${pidfile} ]] && return 0 

    local pid=$(<"${pidfile}")
    einfo "Stopping pppd on ${iface}"
    kill -s TERM "${pid}"
    process_finished "${pid}" /usr/sbin/pppd
	
    eend $?
}