bin/60886: ppp(8) doesn't expand macro MYADDR in `!' commands

[Clemens Fischer]

>Number:         60886
>Category:       bin
>Synopsis:       ppp(8) doesn't expand macro MYADDR in `!' commands
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Sun Jan 04 03:00:11 PST 2004
>Closed-Date:
>Last-Modified:
>Originator:     Clemens Fischer <ino-qc at spotteswoode.de.eu.org>
>Release:        FreeBSD 4.9-STABLE i386
>Organization:
Clemens Fischer
>Environment:
System: FreeBSD spotteswoode.dnsalias.org 4.9-STABLE FreeBSD
4.9-STABLE #15: Fri Jan 2 16:35:22 CET 2004
root at spotteswoode.dnsalias.org:/www/freebsd/obj/www/freebsd/RELENG_4/src/sys/n1
i386

>Description:
        userland-ppp allows custom configuration commands to be
        executed when a PPP connection goes fully functional and when
        the connection is terminated.  administrators can rely on
        several macros beeing expanded to useful values, among them
        HISADDR (IP of peer), INTERFACE (name of interface), MYADDR
        (IP of local PPP interface) etc.

        the relevant configuration lines are (etc/rc.local):

        kldload netgraph || logger "kldload netgraph failed:  $?"

        (etc/ppp/ppp.conf):

        set device PPPoE:xl0
        set speed sync
        set MTU 1492
        set MRU 1492

        my invocation line is:
          "/usr/sbin/ppp -unit 0 -foreground dsl",

        and etc/ppp/ppp.linkup has:
          MYADDR:
            !bg /usr/local/libexec/spott/ppplinkup "LABEL" "MYADDR" "HISADDR" "INTERFACE"

        this script is used to establish various DNS, mail and
        firewall related things.  only "MYADDR" is really used (and
        logged) in this bourne-shell script, and sometimes the very
        first octet of the local peers IP has the leading digits
        replaced by "ay", ie. i get IPs like (from the log):
        "ay7.231.107.141" instead of "217.231.107.141", or
        "ay7.231.106.233" instead of "217.231.106.233" etc.  the
        origin of these faulty expansions of "MYADDR" must be ppp(8),
        as checked by additional "echo" or "printf(1)" statements.
        also, "MYADDR" is only read, never set in any way by my
        scripts.

        the problem doesn't appear every time ppp(8) connects and
        doesn't seem to depend on the actual IP.  a rough estimate
        would be one out of five connections have the "ay-syndrome".

>How-To-Repeat:
	i don't know how to reproduce this problem other than trying
	to connect and verify all the macro expansions, but at my
	workstation type of fbsd installation it first appeared
	2003/11/27 with a system cvsup'ed 2003/11/10 and built later
	the same day.  note that i use the netgraph(4) module for my
	DSL line.

>Fix:
        since the error seems located at the code where MYADDR is
        expanded, i can use the actual value given to the tun0
        interface, thus the following workaround makes the problem
        invisible:

#!/bin/sh
# $Header: /l/dns/RCS/freebsd.sh,v 1.8 2003/12/11 16:46:03 root Exp root $
# freebsd.sh gets parameters from calling /etc/ppp/ppp.linkup & /l/libexec/spott/*link*
#
LABEL="$1" MYADDR="$2" HISADDR="$3" INTERFACE="$4"
logger "LABEL=${LABEL} MYADDR=${MYADDR} HISADDR=${HISADDR} INTERFACE=${INTERFACE}"
#
case "$MYADDR" in
[0-9]*.[0-9]*.[0-9]*.[0-9]*)
        ip_addr="$MYADDR"
        ex="$0 ip_addr:  $ip_addr"
        ;;
*)
        ip_addr=$(ifconfig "${INTERFACE:-tun0}" | grep -- '-->' | awk '{print $2}')
        ex="$0 CORRECTED using ifconfig ip_addr:  $ip_addr"
        ;;
esac
echo "$ip_addr" > /var/spott/ip_addr

regards,

  clemens
>Release-Note:
>Audit-Trail:
>Unformatted:
 SEND-PR: X-send-pr-version: 3.113
 SEND-PR: X-GNATS-Notify: