Hello,
I would like to implement a command line tool, which will be able to open / close , read / write to gtp tunnels. I was able to install the libgtpnl library, but due to lack of documentation I have no idea where to start.
Is there some sort of documentation available for this library?
I need to be able to create and delete tunnels without the GTP-C communication, so just basic command line tool like create-gtp-tunnel + arguments like IPs, version and teid. The GTP-U tunnels must be kernel based. I have the latest kernel with the gtp kernel module loaded.
Any help is appreciated. Thank you, Tomas
Hello,
I found, that there are tools available for this purpose, however they are not compiled on build. By adding the bin_PROGRAMS to the makefile the tools are built. I was too lazy to set up the whole gerrit thing, so I’m sending the patch.
diff --git a/tools/Makefile.am b/tools/Makefile.am index 95aef86..3db095e 100644 --- a/tools/Makefile.am +++ b/tools/Makefile.am @@ -1,5 +1,8 @@ include $(top_srcdir)/Make_global.am
+bin_PROGRAMS = gtp-link \ + gtp-tunnel + check_PROGRAMS = gtp-link \ gtp-tunnel
Tomas
On 15 Feb 2018, at 00:11, Thomas Boros tomas.boros92@gmail.com wrote:
Hello,
I would like to implement a command line tool, which will be able to open / close , read / write to gtp tunnels. I was able to install the libgtpnl library, but due to lack of documentation I have no idea where to start.
Is there some sort of documentation available for this library?
I need to be able to create and delete tunnels without the GTP-C communication, so just basic command line tool like create-gtp-tunnel + arguments like IPs, version and teid. The GTP-U tunnels must be kernel based. I have the latest kernel with the gtp kernel module loaded.
Any help is appreciated. Thank you, Tomas
Hi Thomas,
On Thu, Feb 15, 2018 at 11:06:12AM +0100, Thomas Boros wrote:
+bin_PROGRAMS = gtp-link \
gtp-tunnelcheck_PROGRAMS = gtp-link \ gtp-tunnel
This would have them both in bin_PROGRAMS and in check_PROGRAMS, which is redundant.
In any case bin_PROGRAMS installs those tools, which are really only useful to developers and not for the typical users. I went for an alternative and included them in noinst_PROGRAMS, i.e. they are always being built during 'make' not only 'make check', but they still aren't installed during 'make install'.
See https://gerrit.osmocom.org/6517
Hi Harald,
I’ve also noticed one unusual thing. I noticed, that the the gtp-link app must be running, so the socket remains open. If I kill the application and I have gtp-tunnels set up, the machine responds with and ICMP port unreachable message, but I suppose, this behaviour is ok. Another issue I’ve noticed, I’ve enabled module debugging and I can clearly see, if there is a GTP datagram arriving on the socket to a pdp context, which is not existing, the log says that the datagram is going to be handled in the userspace. However, even if the gtp-link tool is running, the datagrams are not passed to the userspace, they get buffered in the Recieve-Q (checked via netstat). On each packet this queue gets larger, what I assume is not the desired functionality. I guess there is something wrong with the gtp-link tool. Did you encounter such situation? I’m using the latest kernel 4.15.3 and the library is compiled from the osmocom repository.
root@gtpt:~# uname -ar Linux gtpt 4.15.3-041503-generic #201802120730 SMP Mon Feb 12 07:31:14 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux
Tomas
On 16 Feb 2018, at 08:24, Harald Welte laforge@gnumonks.org wrote:
Hi Thomas,
On Thu, Feb 15, 2018 at 11:06:12AM +0100, Thomas Boros wrote:
+bin_PROGRAMS = gtp-link \
gtp-tunnelcheck_PROGRAMS = gtp-link \ gtp-tunnel
This would have them both in bin_PROGRAMS and in check_PROGRAMS, which is redundant.
In any case bin_PROGRAMS installs those tools, which are really only useful to developers and not for the typical users. I went for an alternative and included them in noinst_PROGRAMS, i.e. they are always being built during 'make' not only 'make check', but they still aren't installed during 'make install'.
See https://gerrit.osmocom.org/6517
--
- Harald Welte laforge@gnumonks.org http://laforge.gnumonks.org/
============================================================================ "Privacy in residential applications is a desirable marketing option." (ETSI EN 300 175-7 Ch. A6)
I’m attaching some logs to my previous mail:
Feb 16 09:26:01 gtpt kernel: [ 2044.151300] gtp0: encap_recv sk=000000005f3daa49 Feb 16 09:26:01 gtpt kernel: [ 2044.151302] gtp0: received GTP1U packet Feb 16 09:26:01 gtpt kernel: [ 2044.151303] gtp0: No PDP ctx to decap skb=000000001be38557 Feb 16 09:26:01 gtpt kernel: [ 2044.151304] gtp0: pass up to the process
root@gtpt:~# gtp-link add gtp0 WARNING: attaching dummy socket descriptors. Keep this process running for testing purposes.
Every 1.0s: netstat -aup Fri Feb 16 09:27:29 2018
Active Internet connections (servers and established) Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name udp 0 0 *:3386 *:* 3338/gtp-link udp 0 0 *:bootpc *:* 741/dhclient udp 6144 0 *:2152 *:* 3338/gtp-link
Tomas
On 16 Feb 2018, at 09:00, Thomas Boros tomas.boros92@gmail.com wrote:
Hi Harald,
I’ve also noticed one unusual thing. I noticed, that the the gtp-link app must be running, so the socket remains open. If I kill the application and I have gtp-tunnels set up, the machine responds with and ICMP port unreachable message, but I suppose, this behaviour is ok. Another issue I’ve noticed, I’ve enabled module debugging and I can clearly see, if there is a GTP datagram arriving on the socket to a pdp context, which is not existing, the log says that the datagram is going to be handled in the userspace. However, even if the gtp-link tool is running, the datagrams are not passed to the userspace, they get buffered in the Recieve-Q (checked via netstat). On each packet this queue gets larger, what I assume is not the desired functionality. I guess there is something wrong with the gtp-link tool. Did you encounter such situation? I’m using the latest kernel 4.15.3 and the library is compiled from the osmocom repository.
root@gtpt:~# uname -ar Linux gtpt 4.15.3-041503-generic #201802120730 SMP Mon Feb 12 07:31:14 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux
Tomas
On 16 Feb 2018, at 08:24, Harald Welte laforge@gnumonks.org wrote:
Hi Thomas,
On Thu, Feb 15, 2018 at 11:06:12AM +0100, Thomas Boros wrote:
+bin_PROGRAMS = gtp-link \
gtp-tunnelcheck_PROGRAMS = gtp-link \ gtp-tunnel
This would have them both in bin_PROGRAMS and in check_PROGRAMS, which is redundant.
In any case bin_PROGRAMS installs those tools, which are really only useful to developers and not for the typical users. I went for an alternative and included them in noinst_PROGRAMS, i.e. they are always being built during 'make' not only 'make check', but they still aren't installed during 'make install'.
See https://gerrit.osmocom.org/6517
--
- Harald Welte laforge@gnumonks.org http://laforge.gnumonks.org/
============================================================================ "Privacy in residential applications is a desirable marketing option." (ETSI EN 300 175-7 Ch. A6)
osmocom-net-gprs@lists.osmocom.org
-
Harald Welte -
Thomas Boros