Use the corresponding hash function depending on the version
type. Using ipv4_hashfn was working with GTPv1 because the
TEI is also 32-bits, bit GTPv0 was broken.
Add some instruction in the proper way that can be enabled on the
demand to debug problems. Let's make it quite verbose at this stage
to relax this later.
Make sure debugfs is mounted:
# mount -t debugfs nodev /sys/kernel/debug
To enable:
echo -n 'file gtp.c +p' > /sys/kernel/debug/dynamic_debug/control
To disable:
echo -n 'file gtp.c -p' > /sys/kernel/debug/dynamic_debug/control
More information here on how to use this: http://lwn.net/Articles/434856/
This function allows you to check if there is a MS address or TEID
that already exists in the gtp forwarding base in a very fast way,
without having to dump the entire forwarding base and doing a search
from userspace.
With this fix, osmo-sgsn doesn't ignore our tunneled packet
anymore. It was complaining about incorrect packet length
for received packets.
And osmo-ggsn is working in my testbed :-).
TS 29.060 expresses thing is a quite complicated way just to say
that if any of the optional fields is there, then all optional
fields become mandatory :-).
"This field shall be present if and only if any one or more of the S,
PN and E flags are set.".
So, if any flag is set, we *always* have 4 extra bytes.
We cannot strip the UDP header until we are sure that this is
a data packet, otherwise this passes a malformed packet to
userspace. The header stripping is now the very last operation
in the processing of GTP packets.
We can use this to specify 'gtp0' from openggsn, so we make sure that
it always uses the same tunnel device on creation. If it already exists,
it will return EEXIST. This is used to skip the problem of lacking
NLM_F_ECHO in the rtnetlink link interface that allows us to know the
name of the gtp device that has been dynamically allocated from the
kernel.
And, finally, I don't find any use case for having more than one tunnel
device when integrating this with openggsn.
This patch also adjusts tools/gtp-link-add.c which needs some care, since
it is not yet using any of the library functions. This tools are likely
to be useful for troubleshooting and debugging.
openggsn already sets up the UDP sockets that we need for the control
and user planes of GTP. Since we cannot bind two UDP sockets (one from
userspace and another from the kernel) to the same port, change the
current code to pass the socket descriptors that has been allocated
by openggsn (or whatever daemon which uses the GTP kernel
infrastructure).
Two new attributes are added to set up the tunnel device: IFLA_GTP_FD0
(for GTP0) and IFLA_GTP_FD1 (for GTP1u), which specify the UDP socket
created from userspace. Thus, the GTP kernel code only takes care of
enabling the kernel UDP encapsulation routine.
Fix these compilation warning:
gtp-genl.c:131:8: warning: 'pdp.version' may be used uninitialized in this function [-Wmaybe-uninitialized]
gtp-genl.c:132:8: warning: 'pdp.tid' may be used uninitialized in this function [-Wmaybe-uninitialized]
d CCLD libgtpnl.la
By initializing the pdp object.
This patch adds a gtp_tunnel structure to avoid having to deal with
functions with lots of parameters. This should also help to extend
the interfaces and the gtp_tunnel object without breaking the binary
interface (which will be good by when ipv6 support will be added).
This patch adds the libgtpnl library. Harald mentioned that he wanted
that the specific code that is added is well encapsulated, so let's
start a small library to interact with the GTP kernel module via netlink
interface.
This was done a bit while in the rush, so the interfaces are not nice
at all and the tools need to be ported on top of this library.
This library will be used to integrate openggsn with the GTP kernel
module.
* Conditional check if we can pull the extensions (if any).
* Pull the GTPv1 header (8 bytes) and the extensions (if any).
Tested with emulated replayed pcap traffic, works for me.
Don't use the inner header frag_off, this breaks GTP with fragments.
Instead, inconditionally set the DF flag, this should force us to
fragment the GTP traffic and I think this should also help with wrong
network topologies that result in network loops (that may
encapsulated GTP traffic over and over again).
Other tunnel implementation allows you to configure this.
This patch converts GTP_CMD_CFG_* genetlink commands to rtnl to
configure the socket address and the hashtable. The trick is to
use a workqueue to configure the socket.
This simplifies the netlink interface, now we have two:
* One to bring up the interface and the socket via rtnl.
* Another to configure tunnels / GTP version.
Before the socket configuration was separated from the the device
setup, which was sloppy.
Don't get confused with big GSO packets, we should not send
icmp frag needed as the temporary internal mtu of the linux
stack is not bounded to the real device mtu.
Fix MTU handling by using the real device hardware address length
and substract the IP header + UDP header + GTPvX header.
While at it, remove flags that are not required to be reset.
This patch refactorizes the xmit path to consolidate the common
handling and move the specific IPv4/IPv6 handling to helper
functions. The IPv6 support is incomplete though.
This patch adds the struct gtp_pktinfo that contains the context
information for tunneling this packet. This should help to avoid
functions with lots of parameters.
Tested with IPv4, still working.
Pablo Neira Ayuso