* [PATCH net-next v4 2/3] netlink: specs: add genetlink-legacy spec for GTP
2026-10-10 10:57 [PATCH net-next v4 0/3] gtp: ynl spec for the GTP netlink family, a reply-command fix, and a selftest Anil Kaushik
2026-10-10 10:57 ` [PATCH net-next v4 1/3] gtp: set a valid genl command in PDP context get and dump replies Anil Kaushik
@ 2026-10-10 10:57 ` Anil Kaushik
2026-10-10 10:57 ` [PATCH net-next v4 3/3] selftests: net: add a test for the gtp netlink family Anil Kaushik
2 siblings, 0 replies; 4+ messages in thread
From: Anil Kaushik @ 2026-10-10 10:57 UTC (permalink / raw)
To: Pablo Neira Ayuso, Harald Welte, Donald Hunter, Jakub Kicinski
Cc: David S . Miller, Eric Dumazet, Paolo Abeni, Simon Horman,
Andrew Lunn, Shuah Khan, osmocom-net-gprs, netdev, linux-kernel,
linux-kselftest, Anil Kaushik
The GTP (GPRS Tunnelling Protocol, user plane) generic netlink family
has no YAML specification under Documentation/netlink/specs/, so it
cannot be consumed by the ynl tooling used for user-space clients,
documentation and selftests.
Add a genetlink-legacy spec describing the existing family: the PDP
context management commands (NEWPDP, DELPDP, GETPDP) and the GTP-U echo
request (ECHOREQ), the GTPA_* attribute set, and the "gtp" multicast
group. Command and attribute values are taken from
include/uapi/linux/gtp.h and match it one-to-one. The request
attributes of each command are the ones its handler in
drivers/net/gtp.c reads, and the reply attributes the ones
gtp_genl_fill_info() emits.
This only adds the description; there is no kernel code or uapi change.
Signed-off-by: Anil Kaushik <anilkaushikwireless@gmail.com>
---
Documentation/netlink/specs/gtp.yaml | 171 +++++++++++++++++++++++++++
MAINTAINERS | 1 +
2 files changed, 172 insertions(+)
create mode 100644 Documentation/netlink/specs/gtp.yaml
diff --git a/Documentation/netlink/specs/gtp.yaml b/Documentation/netlink/specs/gtp.yaml
new file mode 100644
index 000000000000..2c61c4353c89
--- /dev/null
+++ b/Documentation/netlink/specs/gtp.yaml
@@ -0,0 +1,171 @@
+# SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)
+---
+name: gtp
+
+protocol: genetlink-legacy
+
+doc: |
+ GPRS Tunnelling Protocol, user plane (GTP-U).
+
+ The gtp netdevice encapsulates and decapsulates user plane packets in
+ GTP-U tunnels (GTPv0 and GTPv1-U, see 3GPP TS 29.060 and TS 29.281).
+ This family manages the PDP contexts that describe the tunnels and
+ triggers GTP-U echo requests. It is driven by user space control planes
+ such as those built on libgtpnl.
+
+kernel-policy: global
+
+attribute-sets:
+ -
+ name: gtp
+ name-prefix: gtpa-
+ attributes:
+ -
+ name: link
+ type: u32
+ doc: ifindex of the gtp netdevice the context is attached to.
+ -
+ name: version
+ type: u32
+ doc: GTP version of the context, 0 for GTPv0 or 1 for GTPv1-U.
+ -
+ name: tid
+ type: u64
+ doc: Tunnel identifier, GTPv0 only.
+ -
+ name: peer-address
+ type: u32
+ byte-order: big-endian
+ display-hint: ipv4
+ doc: |
+ IPv4 address of the remote GSN peer (GGSN or SGSN). Also known
+ as GTPA_SGSN_ADDRESS, kept for legacy user space.
+ -
+ name: ms-address
+ type: u32
+ byte-order: big-endian
+ display-hint: ipv4
+ doc: IPv4 address of the mobile subscriber served by the context.
+ -
+ name: flow
+ type: u16
+ doc: Flow label, GTPv0 only.
+ -
+ name: net-ns-fd
+ type: u32
+ doc: File descriptor of the network namespace of the gtp netdevice.
+ -
+ name: i-tei
+ type: u32
+ doc: Ingress Tunnel Endpoint Identifier, GTPv1-U only.
+ -
+ name: o-tei
+ type: u32
+ doc: Egress Tunnel Endpoint Identifier, GTPv1-U only.
+ -
+ name: pad
+ type: pad
+ -
+ name: peer-addr6
+ type: binary
+ checks:
+ exact-len: 16
+ byte-order: big-endian
+ display-hint: ipv6
+ doc: IPv6 address of the remote GSN peer (GGSN or SGSN).
+ -
+ name: ms-addr6
+ type: binary
+ checks:
+ exact-len: 16
+ byte-order: big-endian
+ display-hint: ipv6
+ doc: IPv6 address of the mobile subscriber served by the context.
+ -
+ name: family
+ type: u8
+ doc: Address family (AF_INET or AF_INET6) of the context addresses.
+
+operations:
+ list:
+ -
+ name: newpdp
+ doc: Create or update a PDP context.
+ attribute-set: gtp
+ value: 0
+ dont-validate: [strict, dump]
+ flags: [admin-perm]
+ do:
+ request: &pdp-attrs
+ attributes:
+ - link
+ - version
+ - tid
+ - peer-address
+ - peer-addr6
+ - ms-address
+ - ms-addr6
+ - flow
+ - i-tei
+ - o-tei
+ - family
+ - net-ns-fd
+ -
+ name: delpdp
+ doc: Delete a PDP context.
+ attribute-set: gtp
+ dont-validate: [strict, dump]
+ flags: [admin-perm]
+ do:
+ request: &pdp-find
+ attributes:
+ - link
+ - version
+ - tid
+ - ms-address
+ - ms-addr6
+ - i-tei
+ - family
+ - net-ns-fd
+ -
+ name: getpdp
+ doc: Get or dump one or more PDP contexts.
+ attribute-set: gtp
+ dont-validate: [strict, dump]
+ flags: [admin-perm]
+ do:
+ request: *pdp-find
+ reply: &pdp-reply
+ attributes:
+ - link
+ - version
+ - tid
+ - peer-address
+ - peer-addr6
+ - ms-address
+ - ms-addr6
+ - flow
+ - i-tei
+ - o-tei
+ - family
+ dump:
+ reply: *pdp-reply
+ -
+ name: echoreq
+ doc: Send a GTP-U echo request to a peer.
+ attribute-set: gtp
+ dont-validate: [strict, dump]
+ flags: [admin-perm]
+ do:
+ request:
+ attributes:
+ - link
+ - version
+ - peer-address
+ - ms-address
+ - net-ns-fd
+
+mcast-groups:
+ list:
+ -
+ name: gtp
diff --git a/MAINTAINERS b/MAINTAINERS
index 51873349ba91..a6e43995ea58 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -11421,6 +11421,7 @@ M: Harald Welte <laforge@gnumonks.org>
L: osmocom-net-gprs@lists.osmocom.org
S: Maintained
T: git git://git.kernel.org/pub/scm/linux/kernel/git/pablo/gtp.git
+F: Documentation/netlink/specs/gtp.yaml
F: drivers/net/gtp.c
GUID PARTITION TABLE (GPT)
--
2.25.1
^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH net-next v4 3/3] selftests: net: add a test for the gtp netlink family
2026-10-10 10:57 [PATCH net-next v4 0/3] gtp: ynl spec for the GTP netlink family, a reply-command fix, and a selftest Anil Kaushik
2026-10-10 10:57 ` [PATCH net-next v4 1/3] gtp: set a valid genl command in PDP context get and dump replies Anil Kaushik
2026-10-10 10:57 ` [PATCH net-next v4 2/3] netlink: specs: add genetlink-legacy spec for GTP Anil Kaushik
@ 2026-10-10 10:57 ` Anil Kaushik
2 siblings, 0 replies; 4+ messages in thread
From: Anil Kaushik @ 2026-10-10 10:57 UTC (permalink / raw)
To: Pablo Neira Ayuso, Harald Welte, Donald Hunter, Jakub Kicinski
Cc: David S . Miller, Eric Dumazet, Paolo Abeni, Simon Horman,
Andrew Lunn, Shuah Khan, osmocom-net-gprs, netdev, linux-kernel,
linux-kselftest, Anil Kaushik
Exercise the gtp generic netlink family through its ynl spec: create a
gtp device, add a PDP context with newpdp, check getpdp dumps it on that
device with the expected TEIDs and addresses, and that delpdp by TEI
removes it. Two more cases check that two contexts are dumped and one
can be deleted by its MS address, and that deleting an unknown context
fails with ENOENT, both by TEI and by MS address.
ynl resolves the family ids once per process, with a CTRL_CMD_GETFAMILY
dump which does not autoload modules, so the gtp device is created
before the family handle: that loads gtp.ko through its rtnl link alias.
The test is skipped when the kernel or iproute2 lack GTP support.
Add a GtpFamily ynl wrapper and register the test.
Signed-off-by: Anil Kaushik <anilkaushikwireless@gmail.com>
---
MAINTAINERS | 1 +
tools/testing/selftests/net/Makefile | 1 +
tools/testing/selftests/net/config | 1 +
tools/testing/selftests/net/gtp.py | 115 ++++++++++++++++++
.../testing/selftests/net/lib/py/__init__.py | 5 +-
tools/testing/selftests/net/lib/py/ynl.py | 8 +-
6 files changed, 128 insertions(+), 3 deletions(-)
create mode 100755 tools/testing/selftests/net/gtp.py
diff --git a/MAINTAINERS b/MAINTAINERS
index a6e43995ea58..8ac817a78bb0 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -11423,6 +11423,7 @@ S: Maintained
T: git git://git.kernel.org/pub/scm/linux/kernel/git/pablo/gtp.git
F: Documentation/netlink/specs/gtp.yaml
F: drivers/net/gtp.c
+F: tools/testing/selftests/net/gtp.py
GUID PARTITION TABLE (GPT)
M: Davidlohr Bueso <dave@stgolabs.net>
diff --git a/tools/testing/selftests/net/Makefile b/tools/testing/selftests/net/Makefile
index d4ca82fec0b4..6b54e04a6430 100644
--- a/tools/testing/selftests/net/Makefile
+++ b/tools/testing/selftests/net/Makefile
@@ -46,6 +46,7 @@ TEST_PROGS := \
fq_band_pktlimit.sh \
gre_gso.sh \
gre_ipv6_lladdr.sh \
+ gtp.py \
icmp.sh \
icmp_redirect.sh \
io_uring_zerocopy_tx.sh \
diff --git a/tools/testing/selftests/net/config b/tools/testing/selftests/net/config
index 737e7e6327b3..c4534e15fb7a 100644
--- a/tools/testing/selftests/net/config
+++ b/tools/testing/selftests/net/config
@@ -15,6 +15,7 @@ CONFIG_DEBUG_INFO_BTF=y
CONFIG_DEBUG_INFO_BTF_MODULES=n
CONFIG_DUMMY=y
CONFIG_GENEVE=m
+CONFIG_GTP=m
CONFIG_IFB=y
CONFIG_INET_DIAG=y
CONFIG_INET_ESP=y
diff --git a/tools/testing/selftests/net/gtp.py b/tools/testing/selftests/net/gtp.py
new file mode 100755
index 000000000000..b307699b3c1e
--- /dev/null
+++ b/tools/testing/selftests/net/gtp.py
@@ -0,0 +1,115 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0
+
+"""Tests for the gtp netlink family."""
+
+import errno
+
+from lib.py import ksft_run, ksft_exit
+from lib.py import ksft_eq, ksft_in, ksft_not_in, ksft_raises
+from lib.py import KsftSkipEx
+from lib.py import NetNS, NetNSEnter
+from lib.py import GtpFamily, NlError
+from lib.py import CmdExitFailure
+from lib.py import ip, defer
+
+
+def _setup(ns):
+ """Return a gtp family handle, and the ifindex of a new gtp device.
+
+ Create the device first: that loads gtp.ko through its rtnl link
+ alias. ynl resolves the family ids once per process, with a
+ CTRL_CMD_GETFAMILY dump which does not autoload modules, so the
+ family must be registered before the first family handle is created.
+ """
+ try:
+ ip("link add gtp0 type gtp role ggsn", ns=str(ns))
+ except CmdExitFailure as e:
+ raise KsftSkipEx("no gtp support (CONFIG_GTP, iproute2)") from e
+ defer(ip, "link del gtp0", ns=str(ns))
+ ip("link set gtp0 up", ns=str(ns))
+ link = ip("-d link show gtp0", ns=str(ns), json=True)[0]["ifindex"]
+
+ with NetNSEnter(str(ns)):
+ gtp = GtpFamily()
+
+ return gtp, link
+
+
+def _contexts(gtp, link):
+ return [c for c in gtp.getpdp({}, dump=True) if c.get("link") == link]
+
+
+def _iteis(contexts):
+ return [c.get("i-tei") for c in contexts]
+
+
+def add_del_pdp(ns) -> None:
+ """Add a PDP context, query it, then delete it by TEI.
+
+ The dump must return the context with the link, TEIDs and addresses
+ it was created with, and it must be gone after the delete. The delete
+ only identifies the context by its TEI, to use the GTPv1 TEI lookup.
+ """
+ gtp, link = _setup(ns)
+
+ gtp.newpdp({"link": link, "version": 1,
+ "i-tei": 0x100, "o-tei": 0x200,
+ "ms-address": "10.0.0.1", "peer-address": "192.0.2.1"})
+
+ pdp = [c for c in _contexts(gtp, link) if c.get("i-tei") == 0x100]
+ ksft_eq(len(pdp), 1)
+ ksft_eq(pdp[0]["o-tei"], 0x200)
+ ksft_eq(pdp[0]["ms-address"], "10.0.0.1")
+ ksft_eq(pdp[0]["peer-address"], "192.0.2.1")
+
+ gtp.delpdp({"link": link, "version": 1, "i-tei": 0x100})
+ ksft_not_in(0x100, _iteis(_contexts(gtp, link)))
+
+
+def add_two_pdp(ns) -> None:
+ """Add two PDP contexts, check both are dumped, delete one by address.
+
+ The delete identifies the context by its MS address, and must leave
+ the other context in place.
+ """
+ gtp, link = _setup(ns)
+
+ for i_tei, o_tei, ms in ((0x111, 0x211, "10.0.1.1"),
+ (0x112, 0x212, "10.0.1.2")):
+ gtp.newpdp({"link": link, "version": 1,
+ "i-tei": i_tei, "o-tei": o_tei,
+ "ms-address": ms, "peer-address": "192.0.2.5"})
+
+ iteis = _iteis(_contexts(gtp, link))
+ ksft_in(0x111, iteis)
+ ksft_in(0x112, iteis)
+
+ gtp.delpdp({"link": link, "version": 1, "ms-address": "10.0.1.1"})
+ iteis = _iteis(_contexts(gtp, link))
+ ksft_not_in(0x111, iteis)
+ ksft_in(0x112, iteis)
+
+
+def del_unknown_pdp(ns) -> None:
+ """Deleting a context that was never added must fail with ENOENT.
+
+ Both lookups are checked: by TEI, and by MS address.
+ """
+ gtp, link = _setup(ns)
+
+ for attrs in ({"i-tei": 0x999}, {"ms-address": "10.9.9.9"}):
+ with ksft_raises(NlError) as cm:
+ gtp.delpdp({"link": link, "version": 1, **attrs})
+ ksft_eq(cm.exception.error, errno.ENOENT)
+
+
+def main() -> None:
+ """Run the PDP context tests in a temporary netns."""
+ with NetNS() as ns:
+ ksft_run([add_del_pdp, add_two_pdp, del_unknown_pdp], args=(ns,))
+ ksft_exit()
+
+
+if __name__ == "__main__":
+ main()
diff --git a/tools/testing/selftests/net/lib/py/__init__.py b/tools/testing/selftests/net/lib/py/__init__.py
index 71df5880b356..e269a260d58e 100644
--- a/tools/testing/selftests/net/lib/py/__init__.py
+++ b/tools/testing/selftests/net/lib/py/__init__.py
@@ -18,7 +18,7 @@ from .utils import CmdExitFailure, fd_read_timeout, cmd, bkg, defer, \
from .bpf import bpf_map_set, bpf_map_dump, bpf_prog_map_ids
from .ynl import NlError, NlctrlFamily, YnlFamily, \
EthtoolFamily, NetdevFamily, RtnlFamily, RtnlAddrFamily, RtnlRouteFamily
-from .ynl import NetshaperFamily, DevlinkFamily, PSPFamily, Netlink
+from .ynl import NetshaperFamily, DevlinkFamily, GtpFamily, PSPFamily, Netlink
__all__ = ["KSRC",
"KsftFailEx", "KsftSkipEx", "KsftXfailEx", "ksft_pr", "ksft_eq",
@@ -32,6 +32,7 @@ __all__ = ["KSRC",
"wait_port_listen", "ctl_file_write", "wait_file", "tool", "tc",
"bpf_map_set", "bpf_map_dump", "bpf_prog_map_ids",
"NetdevSim", "NetdevSimDev",
- "NetshaperFamily", "DevlinkFamily", "PSPFamily", "NlError",
+ "NetshaperFamily", "DevlinkFamily", "GtpFamily", "PSPFamily",
+ "NlError",
"YnlFamily", "EthtoolFamily", "NetdevFamily", "RtnlFamily",
"NlctrlFamily", "RtnlAddrFamily", "RtnlRouteFamily", "Netlink"]
diff --git a/tools/testing/selftests/net/lib/py/ynl.py b/tools/testing/selftests/net/lib/py/ynl.py
index 08deff756f29..7edb74971023 100644
--- a/tools/testing/selftests/net/lib/py/ynl.py
+++ b/tools/testing/selftests/net/lib/py/ynl.py
@@ -31,7 +31,7 @@ __all__ = [
"NlError", "NlPolicy", "Netlink", "YnlFamily", "SPEC_PATH",
"EthtoolFamily", "RtnlFamily", "RtnlAddrFamily", "RtnlRouteFamily",
"NetdevFamily", "NetshaperFamily", "NlctrlFamily", "DevlinkFamily",
- "PSPFamily",
+ "GtpFamily", "PSPFamily",
]
#
@@ -85,3 +85,9 @@ class PSPFamily(YnlFamily):
def __init__(self, recv_size=0):
super().__init__((SPEC_PATH / Path('psp.yaml')).as_posix(),
schema='', recv_size=recv_size)
+
+
+class GtpFamily(YnlFamily):
+ def __init__(self, recv_size=0):
+ super().__init__((SPEC_PATH / Path('gtp.yaml')).as_posix(),
+ schema='', recv_size=recv_size)
--
2.25.1
^ permalink raw reply [flat|nested] 4+ messages in thread