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p120ph37/ip-up

Created June 30, 2014 16:27
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  1. p120ph37 created this gist Jun 30, 2014.
    109 changes: 109 additions & 0 deletions ip-up
    View file
    Original file line number Diff line number Diff line change
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    #!/bin/sh
    ####################################################
    ## ##
    ## PPP VPN split-network/split-DNS script for OSX ##
    ## by Aaron Meriwether ##
    ## ##
    ## installation: ##
    ## sudo cp thisfile /etc/ppp/ip-up ##
    ## sudo chmod 755 /etc/ppp/ip-up ##
    ## ##
    ####################################################

    ##################
    ## begin config...

    # Define per-VPN-server settings here...
    SERVERS[0]="vpn.example.org" # must match the server name set in Network Preferences.
    NETWORKS[0]="192.168.2.0/24 192.168.3.0/24" # only networks besides the VPN LAN itself!
    DOMAINS[0]="example.org" # domains which should use the VPN's DNS resolver when connected.

    SERVERS[1]="vpn.mit.edu"
    NETWORKS[1]="" # an empty network list is acceptable if you are only interested in the DNS aspects
    DOMAINS[1]="staff.mit.edu athena.mit.edu"

    SERVERS[2]="vpn.rogers.com"
    NETWORKS[2]="172.16.7.128/25 205.150.67.0/24"
    DOMAINS[2]="" # likewise, an empty DNS list is acceptable if you are only interested in the network aspects

    # set to /dev/null if you object to debugging output.
    DEBUGFILE=/tmp/ip-up-debug.txt

    ## end config...
    #################


    # When the ppp link comes up, this script is called with the following
    # parameters
    # $1 the interface name used by pppd (e.g. ppp3)
    # $2 the tty device name
    # $3 the tty device speed
    # $4 the local IP address for the interface
    # $5 the remote IP address
    # $6 the parameter specified by the 'ipparam' option to pppd
    # (when used with a VPN configured via Network Preferences,
    # $6 seems to contain the IP address of the gateway over
    # which the VPN traffic passes. This might be useful in
    # ip-up scripts which need to avoid breaking the route
    # used by pppd itself.)

    PATH=/usr/bin:/bin:/usr/sbin:/sbin

    # Generic array operation.
    # e.g.: indexOf "something" "${myArray[@]}"
    # note the double quotes around the array and the use of [@] not [*]
    indexOf() {
    local s="$1"; shift; local a=( "$@" ) i
    for (( i = 0; i < ${#@}; i++ )); do
    if [ "${a[$i]}" == "$s" ]; then echo $i; return; fi
    done
    }

    # Given an interface name, find the corresponding scutil service key.
    if2service() {
    local i
    for i in $(echo "list State:/Network/Service/[^/]+/PPP" | scutil | cut -d/ -f4); do
    if [ "$(echo show State:/Network/Service/$i/PPP | scutil | grep InterfaceName | cut -d' ' -f5)" == "$1" ]; then echo $i; return; fi
    done
    }

    # Given a network service key (specifically a PPP service), get the server name (as set in Network Preferences).
    getPppServerName() {
    echo show Setup:/Network/Service/$1/PPP | scutil | grep CommRemoteAddress | cut -d' ' -f5
    }

    echo "$(date +'%Y-%m-%d %T %Z') $0 1=$1 2=$2 3=$3 4=$4 5=$5 6=$6" >> $DEBUGFILE
    SERVICE="$(if2service $1)"
    echo "Service: $SERVICE" >> $DEBUGFILE
    SERVER="$(getPppServerName $SERVICE)"
    echo "Server Name: $SERVER" >> $DEBUGFILE
    i=$(indexOf "$SERVER" "${SERVERS[@]}")
    if [ -z "$i" ]; then
    echo "No special configuration found for this VPN server." >> $DEBUGFILE
    exit
    fi

    if [ -n "$(echo show State:/Network/Service/$SERVICE/IPv4 | scutil | grep OverridePrimary)" ]; then
    echo "Clearing the 'Send all traffic over VPN connection' flag" >> $DEBUGFILE
    scutil <<-END
    get State:/Network/Service/$SERVICE/IPv4
    d.remove OverridePrimary
    set State:/Network/Service/$SERVICE/IPv4
    END
    fi

    if [ -n "${NETWORKS[$i]}" ]; then
    for n in ${NETWORKS[$i]}; do
    echo "Adding route for network $n" >> $DEBUGFILE
    route -n add -net $n $5
    done
    fi

    if [ -n "${DOMAINS[$i]}" ]; then
    echo "Limiting DNS over the VPN to these domains: ${DOMAINS[$i]}"
    scutil <<-END
    get State:/Network/Service/$SERVICE/DNS
    d.add SupplementalMatchDomains * ${DOMAINS[$i]}
    set State:/Network/Service/$SERVICE/DNS
    END
    fi