Hi Pablo,
----- On Jan 24, 2017, at 8:03 PM, pablo pablo@netfilter.org wrote:
Hi Andreas,
On Tue, Jan 24, 2017 at 06:24:02PM +0100, Andreas Schultz wrote:
enable userspace to send error replies for invalid tunnels
Signed-off-by: Andreas Schultz aschultz@tpip.net
drivers/net/gtp.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/net/gtp.c b/drivers/net/gtp.c index 912721e..c607333 100644 --- a/drivers/net/gtp.c +++ b/drivers/net/gtp.c @@ -198,12 +198,12 @@ static int gtp0_udp_encap_recv(struct gtp_dev *gtp, struct sk_buff *skb, pctx = gtp0_pdp_find(gtp, be64_to_cpu(gtp0->tid)); if (!pctx) { netdev_dbg(gtp->dev, "No PDP ctx to decap skb=%p\n", skb);
return -1;
return 1;}
if (!gtp_check_src_ms(skb, pctx, hdrlen)) { netdev_dbg(gtp->dev, "No PDP ctx for this MS\n");
return -1;
return 1;So userspace gets the packet that we cannot forward. I guess your userspace codebase performs this sanity checks again so you can send the appropriate error reply?
For TEID /= 0, the only reply is a T-PDU of type error indication. There is no cause specified. So I don't actually have to repeat the check. TEID == 0 is more interesting, this tells userspace that it tried to send on an invalid tunnel and should tear it down.
If you like, you can have a look at the userspace code. The relevant piece is at https://github.com/travelping/gtp_u_kmod/blob/master/src/gtp_u_kmod_port.erl...
But be warned, it's written in Erlang ;-)
Andreas
}
/* Get rid of the GTP + UDP headers. */ @@ -247,12 +247,12 @@ static int gtp1u_udp_encap_recv(struct gtp_dev *gtp, struct sk_buff *skb, pctx = gtp1_pdp_find(gtp, ntohl(gtp1->tid)); if (!pctx) { netdev_dbg(gtp->dev, "No PDP ctx to decap skb=%p\n", skb);
return -1;
return 1;}
if (!gtp_check_src_ms(skb, pctx, hdrlen)) { netdev_dbg(gtp->dev, "No PDP ctx for this MS\n");
return -1;
return 1;}
/* Get rid of the GTP + UDP headers. */
-- 2.10.2