All, The below is in reference to Debian bug #494795: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=494795
Essentially, being that I am not a kernel hacker, I am out of my depth here. I would appreciate it if someone who is knowledgable about this could comment on it. Regards, -Roberto On Tue, Sep 23, 2008 at 05:05:13PM +0400, Alexey L. Smirnov wrote: > Hello, > > It seems I found a possible source of this bug. > The problem is in the way the pppol2tp driver initializes > internal kernel tunnel and socket structures. It implicitly assumes > that you want to use the kernel-based tunnel immediately after > you've got a peer tunnel id. This means you must prepare kernel > socket as follows > > struct sockaddr_pppol2tp sax; > int fd, session_fd; > > fd = socket(AF_PPPOX, SOCK_DGRAM, PX_PROTO_OL2TP); > sax.sa_family = AF_PPPOX; > sax.sa_protocol = PX_PROTO_OL2TP; > sax.pppol2tp.fd = tunnel_fd; > sax.pppol2tp.addr.sin_addr.s_addr = addr->sin_addr.s_addr; > sax.pppol2tp.addr.sin_port = addr->sin_port; > sax.pppol2tp.addr.sin_family = AF_INET; > sax.pppol2tp.s_tunnel = tunnel_id; > sax.pppol2tp.s_session = 0; > sax.pppol2tp.d_tunnel = peer_tunnel_id; > sax.pppol2tp.d_session = 0; > > session_fd = connect(fd, (struct sockaddr *)&sax, sizeof(sax)); > > Note, that s_session, d_session members must be 0 and you must perform > connect() call. > Only in this case you get properly prepared sockets. > > Now, take a look at init_network() function. They use only socket() call to > prepare kernel sockets > and this is not enough. Thus, when they make connect() to the kernel socket > in start_pppd(), they > get this bug. > > To test this, I moved the kernel support code from init_network() to > start_pppd() and > add modification of the above initialization code. The bug disappeared. > However, this is not whole story. When kernel support is on, pppd uses plugin > pppol2tp.so, > which is not present in Debian repositories (but present in openltp). > So, I'm still unable to get xl2tpd work with kernel support. > > > -- Roberto C. Sánchez http://people.connexer.com/~roberto http://www.connexer.com
signature.asc
Description: Digital signature
