Hi Pablo,
----- On Jan 24, 2017, at 8:03 PM, pablo pablo(a)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(a)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.er…
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