i386/152569: Multiple ppp connections and routing table problem with poptop

[martin]

>Number:         152569
>Category:       i386
>Synopsis:       Multiple ppp connections and routing table problem with poptop
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    freebsd-i386
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Thu Nov 25 11:00:21 UTC 2010
>Closed-Date:
>Last-Modified:
>Originator:     martin
>Release:        7.3-RELEASE-p2 #0 and 8.1-RELEASE #0
>Organization:
cifacom
>Environment:
FreeBSD services.static.cifap.lan 7.3-RELEASE-p2 FreeBSD 7.3-RELEASE-p2 #0: Wed Sep 15 17:04:16 CEST 2010     root at services.cifap.lan:/usr/obj/usr/src/sys/GENERIC  i386

and

FreeBSD pptpsrv 8.1-RELEASE FreeBSD 8.1-RELEASE #0: Mon Jul 19 02:55:53 UTC 2010     root at almeida.cse.buffalo.edu:/usr/obj/usr/src/sys/GENERIC  i386
>Description:
Freebsd running as a pptp vpn with poptop. 

When they are multiple clients connected to the vpn server and the first client disconnects first, the routing table is altered too much.

When the first client connects

# netstat -rn | grep tun
10.1.1.131         10.1.1.130         UGH         0        1   tun0
ff01:5::/32                       link#5                        UC         tun0
ff02::%tun0/32                    fe80::250:baff:fe21:69ec%tun0 UGC        tun0

There is no problem, traffic is ok and routing table too.

After the second client connects

# netstat -rn | grep tun
10.1.1.131         10.1.1.130         UGH         0        6   tun0
10.1.1.132         10.1.1.130         UGH         0        0   tun1
ff01:5::/32                       link#5                        UC         tun0
ff01:6::/32                       link#6                        UC         tun1
ff02::%tun0/32                    fe80::250:baff:fe21:69ec%tun0 UGC        tun0
ff02::%tun1/32                    fe80::250:baff:fe21:69ec%tun1 UGC        tun1

Everything is ok too

But when the first client disconnects the routing table changes to this

# netstat -rn | grep tun
ff01:6::/32                       link#6                        UC         tun1
ff02::%tun1/32                    fe80::250:baff:fe21:69ec%tun1 UGC        tun1

and others client's traffic stops too.

This problem does not occur when the second client closes his connection first

# netstat -rn | grep tun
10.1.1.133         10.1.1.130         UGH         0        0   tun1
10.1.1.138         10.1.1.130         UGH         0       14   tun0
ff01:5::/32                       link#5                        UC         tun0
ff01:6::/32                       link#6                        UC         tun1
ff02::%tun0/32                    fe80::250:baff:fe21:69ec%tun0 UGC        tun0
ff02::%tun1/32                    fe80::250:baff:fe21:69ec%tun1 UGC        tun1

# netstat -rn | grep tun
10.1.1.138         10.1.1.130         UGH         0       62   tun0
ff01:5::/32                       link#5                        UC         tun0
ff02::%tun0/32                    fe80::250:baff:fe21:69ec%tun0 UGC        tun0


I can reproduce this on the old (7.1 prerelease) and the new (7.3 release) pptp vpn servers. I can also reproduce it with a freshly 8.1 release installed system on a test laptop. 

I tried searching forums, mailing list, and bug reports but don't find anything that can help me with this. 

Sorry for the raw text, i don't know how to add some format tags. 

Thanks,
>How-To-Repeat:
Install poptop and put this in the /usr/local/etc/pptpd.conf file

# egrep "^[aA-zZ]" /usr/local/etc/pptpd.conf
option pptpd
debug
logwtmp
remoteip 10.1.1.111-120
listen 10.1.1.253

Put this in the /etc/ppp/ppp.conf file

# egrep -v "^#" /etc/ppp/ppp.conf

pptpd:
 set escape 0xff
 set device localhost:pptp
 set dial
 set timeout 0
 set log Phase Chat Connect LCP IPCP IPV6CP CCP tun command
 set ifaddr 10.1.1.110 10.1.1.111-10.1.1.120 255.255.255.255

 set mppe 128 stateful
 enable MSCHAPv2
 disable deflate pred1 lqr
 deny deflate pred1 lqr

 disable ipv6cp

 accept dns
 set dns 10.1.1.253
 set nbns 10.1.1.204

 enable proxy


Enable ip forwarding and arpproxing

sysctl net.inet.ip.forwarding=1
sysctl net.link.ether.inet.proxyall=1
>Fix:
Do not have any

>Release-Note:
>Audit-Trail:
>Unformatted: