* [PATCH net-next] selftests: openvswitch: add dec_ttl action support and test
@ 2026-05-14 9:27 Minxi Hou
2026-05-14 13:48 ` Aaron Conole
0 siblings, 1 reply; 3+ messages in thread
From: Minxi Hou @ 2026-05-14 9:27 UTC (permalink / raw)
To: netdev
Cc: aconole, davem, echaudro, edumazet, horms, i.maximets, kuba,
pabeni, shuah, dev, i.maximets, linux-kselftest, Minxi Hou
Add dec_ttl action support to the OVS kernel datapath selftest
framework:
- Add DecTtl nested NLA class to ovs-dpctl.py with proper
OVS_DEC_TTL_ATTR_ACTION sub-attribute handling
- Add parse support for dec_ttl(<inner_actions>) action string
following the same pattern as clone()
- Add dpstr output formatting for dec_ttl actions
- Add test_dec_ttl() to openvswitch.sh that verifies:
* Normal TTL packets are forwarded after decrement
* TTL=1 packets are dropped (TTL expiry)
* Graceful skip via ksft_skip if kernel lacks dec_ttl support
The DecTtl class uses late-binding type resolution to reference
ovsactions for its inner action list, avoiding circular references
at class definition time.
Tested with vng on x86_64, all OVS selftests pass.
Signed-off-by: Minxi Hou <houminxi@gmail.com>
---
.../selftests/net/openvswitch/openvswitch.sh | 55 +++++++++++++++++++
.../selftests/net/openvswitch/ovs-dpctl.py | 39 ++++++++++++-
2 files changed, 92 insertions(+), 2 deletions(-)
diff --git a/tools/testing/selftests/net/openvswitch/openvswitch.sh b/tools/testing/selftests/net/openvswitch/openvswitch.sh
index 3cdd953f6813..200c36c4d7bf 100755
--- a/tools/testing/selftests/net/openvswitch/openvswitch.sh
+++ b/tools/testing/selftests/net/openvswitch/openvswitch.sh
@@ -28,6 +28,7 @@ tests="
tunnel_metadata ovs: test extraction of tunnel metadata
tunnel_refcount ovs: test tunnel vport reference cleanup
drop_reason drop: test drop reasons are emitted
+ dec_ttl ttl: dec_ttl action decrements IP TTL
psample psample: Sampling packets with psample"
info() {
@@ -244,6 +245,60 @@ usage() {
}
+test_dec_ttl() {
+ sbx_add "test_dec_ttl" || return $?
+ ovs_add_dp "test_dec_ttl" decttl || return 1
+
+ info "create namespaces"
+ for ns in client server; do
+ ovs_add_netns_and_veths "test_dec_ttl" "decttl" "$ns" \
+ "${ns:0:1}0" "${ns:0:1}1" || return 1
+ done
+
+ ip netns exec client ip addr add 10.0.0.1/24 dev c1
+ ip netns exec client ip link set c1 up
+ ip netns exec server ip addr add 10.0.0.2/24 dev s1
+ ip netns exec server ip link set s1 up
+
+ # Probe: check if kernel supports dec_ttl action.
+ ovs_add_flow "test_dec_ttl" decttl \
+ 'in_port(1),eth(),eth_type(0x0800),ipv4()' \
+ 'dec_ttl()' &>/dev/null
+ if [ $? == 1 ]; then
+ info "no support for dec_ttl - skipping"
+ ovs_exit_sig
+ return $ksft_skip
+ fi
+
+ ovs_del_flows "test_dec_ttl" decttl
+
+ # ARP flows (bidirectional)
+ ovs_add_flow "test_dec_ttl" decttl \
+ 'in_port(1),eth(),eth_type(0x0806),arp()' '2' || return 1
+ ovs_add_flow "test_dec_ttl" decttl \
+ 'in_port(2),eth(),eth_type(0x0806),arp()' '1' || return 1
+
+ # IP flows with dec_ttl action
+ ovs_add_flow "test_dec_ttl" decttl \
+ 'in_port(1),eth(),eth_type(0x0800),ipv4()' \
+ 'dec_ttl(),2' || return 1
+ ovs_add_flow "test_dec_ttl" decttl \
+ 'in_port(2),eth(),eth_type(0x0800),ipv4()' \
+ 'dec_ttl(),1' || return 1
+
+ info "verify connectivity with dec_ttl"
+ ovs_sbx "test_dec_ttl" ip netns exec client ping -c 1 -W 2 \
+ 10.0.0.2 || return 1
+
+ info "verify TTL=1 is dropped by dec_ttl"
+ ovs_sbx "test_dec_ttl" ip netns exec client ping -c 1 -W 2 \
+ -t 1 10.0.0.2 >/dev/null 2>&1 \
+ && { info "FAIL: ping should fail with TTL=1 and dec_ttl"
+ return 1; }
+
+ return 0
+}
+
# psample test
# - use psample to observe packets
test_psample() {
diff --git a/tools/testing/selftests/net/openvswitch/ovs-dpctl.py b/tools/testing/selftests/net/openvswitch/ovs-dpctl.py
index bbe35e2718d2..a73ca98d7aef 100644
--- a/tools/testing/selftests/net/openvswitch/ovs-dpctl.py
+++ b/tools/testing/selftests/net/openvswitch/ovs-dpctl.py
@@ -388,11 +388,19 @@ class ovsactions(nla):
("OVS_ACTION_ATTR_CLONE", "recursive"),
("OVS_ACTION_ATTR_CHECK_PKT_LEN", "none"),
("OVS_ACTION_ATTR_ADD_MPLS", "none"),
- ("OVS_ACTION_ATTR_DEC_TTL", "none"),
+ ("OVS_ACTION_ATTR_DEC_TTL", "DecTtl"),
("OVS_ACTION_ATTR_DROP", "uint32"),
("OVS_ACTION_ATTR_PSAMPLE", "psample"),
)
+ class DecTtl(nla):
+ nla_flags = NLA_F_NESTED
+
+ nla_map = (
+ ("OVS_DEC_TTL_ATTR_UNSPEC", "none"),
+ ("OVS_DEC_TTL_ATTR_ACTION", "actions"),
+ )
+
class psample(nla):
nla_flags = NLA_F_NESTED
@@ -632,6 +640,13 @@ class ovsactions(nla):
print_str += "ct_clear"
elif field[0] == "OVS_ACTION_ATTR_POP_VLAN":
print_str += "pop_vlan"
+ elif field[0] == "OVS_ACTION_ATTR_DEC_TTL":
+ datum = self.get_attr(field[0])
+ print_str += "dec_ttl("
+ subacts = datum.get_attr("OVS_DEC_TTL_ATTR_ACTION")
+ if subacts and subacts.get("attrs"):
+ print_str += subacts.dpstr(more)
+ print_str += ")"
elif field[0] == "OVS_ACTION_ATTR_POP_ETH":
print_str += "pop_eth"
elif field[0] == "OVS_ACTION_ATTR_POP_NSH":
@@ -725,7 +740,21 @@ class ovsactions(nla):
actstr = actstr[strspn(actstr, ", ") :]
parsed = True
- if parse_starts_block(actstr, "clone(", False):
+ if parse_starts_block(actstr, "dec_ttl(", False):
+ parencount += 1
+ subacts = ovsactions()
+ actstr = actstr[len("dec_ttl("):]
+ parsedLen = subacts.parse(actstr)
+ decttl = ovsactions.DecTtl()
+ decttl["attrs"].append(
+ ("OVS_DEC_TTL_ATTR_ACTION", subacts)
+ )
+ self["attrs"].append(
+ ("OVS_ACTION_ATTR_DEC_TTL", decttl)
+ )
+ actstr = actstr[parsedLen:]
+ parsed = True
+ elif parse_starts_block(actstr, "clone(", False):
parencount += 1
subacts = ovsactions()
actstr = actstr[len("clone("):]
@@ -896,6 +925,12 @@ class ovsactions(nla):
return (totallen - len(actstr))
+# pyroute2 resolves nla_map types via getattr(self, name).
+# DecTtl needs "actions" to resolve to ovsactions, but
+# ovsactions is not defined when DecTtl class body runs.
+ovsactions.DecTtl.actions = ovsactions
+
+
class ovskey(nla):
nla_flags = NLA_F_NESTED
nla_map = (
--
2.53.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH net-next] selftests: openvswitch: add dec_ttl action support and test
2026-05-14 9:27 [PATCH net-next] selftests: openvswitch: add dec_ttl action support and test Minxi Hou
@ 2026-05-14 13:48 ` Aaron Conole
2026-05-14 14:12 ` Minxi Hou
0 siblings, 1 reply; 3+ messages in thread
From: Aaron Conole @ 2026-05-14 13:48 UTC (permalink / raw)
To: Minxi Hou
Cc: netdev, davem, echaudro, edumazet, horms, i.maximets, kuba,
pabeni, shuah, dev, i.maximets, linux-kselftest, Eric Garver
Minxi Hou <houminxi@gmail.com> writes:
> Add dec_ttl action support to the OVS kernel datapath selftest
> framework:
>
> - Add DecTtl nested NLA class to ovs-dpctl.py with proper
> OVS_DEC_TTL_ATTR_ACTION sub-attribute handling
> - Add parse support for dec_ttl(<inner_actions>) action string
> following the same pattern as clone()
> - Add dpstr output formatting for dec_ttl actions
> - Add test_dec_ttl() to openvswitch.sh that verifies:
> * Normal TTL packets are forwarded after decrement
> * TTL=1 packets are dropped (TTL expiry)
> * Graceful skip via ksft_skip if kernel lacks dec_ttl support
>
> The DecTtl class uses late-binding type resolution to reference
> ovsactions for its inner action list, avoiding circular references
> at class definition time.
>
> Tested with vng on x86_64, all OVS selftests pass.
>
> Signed-off-by: Minxi Hou <houminxi@gmail.com>
> ---
> .../selftests/net/openvswitch/openvswitch.sh | 55 +++++++++++++++++++
> .../selftests/net/openvswitch/ovs-dpctl.py | 39 ++++++++++++-
> 2 files changed, 92 insertions(+), 2 deletions(-)
>
> diff --git a/tools/testing/selftests/net/openvswitch/openvswitch.sh b/tools/testing/selftests/net/openvswitch/openvswitch.sh
> index 3cdd953f6813..200c36c4d7bf 100755
> --- a/tools/testing/selftests/net/openvswitch/openvswitch.sh
> +++ b/tools/testing/selftests/net/openvswitch/openvswitch.sh
> @@ -28,6 +28,7 @@ tests="
> tunnel_metadata ovs: test extraction of tunnel metadata
> tunnel_refcount ovs: test tunnel vport reference cleanup
> drop_reason drop: test drop reasons are emitted
> + dec_ttl ttl: dec_ttl action decrements IP TTL
> psample psample: Sampling packets with psample"
>
> info() {
> @@ -244,6 +245,60 @@ usage() {
> }
>
>
> +test_dec_ttl() {
> + sbx_add "test_dec_ttl" || return $?
> + ovs_add_dp "test_dec_ttl" decttl || return 1
> +
> + info "create namespaces"
> + for ns in client server; do
> + ovs_add_netns_and_veths "test_dec_ttl" "decttl" "$ns" \
> + "${ns:0:1}0" "${ns:0:1}1" || return 1
> + done
> +
> + ip netns exec client ip addr add 10.0.0.1/24 dev c1
> + ip netns exec client ip link set c1 up
> + ip netns exec server ip addr add 10.0.0.2/24 dev s1
> + ip netns exec server ip link set s1 up
> +
> + # Probe: check if kernel supports dec_ttl action.
> + ovs_add_flow "test_dec_ttl" decttl \
> + 'in_port(1),eth(),eth_type(0x0800),ipv4()' \
> + 'dec_ttl()' &>/dev/null
> + if [ $? == 1 ]; then
> + info "no support for dec_ttl - skipping"
> + ovs_exit_sig
> + return $ksft_skip
> + fi
> +
> + ovs_del_flows "test_dec_ttl" decttl
> +
> + # ARP flows (bidirectional)
> + ovs_add_flow "test_dec_ttl" decttl \
> + 'in_port(1),eth(),eth_type(0x0806),arp()' '2' || return 1
> + ovs_add_flow "test_dec_ttl" decttl \
> + 'in_port(2),eth(),eth_type(0x0806),arp()' '1' || return 1
> +
> + # IP flows with dec_ttl action
> + ovs_add_flow "test_dec_ttl" decttl \
> + 'in_port(1),eth(),eth_type(0x0800),ipv4()' \
> + 'dec_ttl(),2' || return 1
> + ovs_add_flow "test_dec_ttl" decttl \
> + 'in_port(2),eth(),eth_type(0x0800),ipv4()' \
> + 'dec_ttl(),1' || return 1
> +
> + info "verify connectivity with dec_ttl"
> + ovs_sbx "test_dec_ttl" ip netns exec client ping -c 1 -W 2 \
> + 10.0.0.2 || return 1
> +
> + info "verify TTL=1 is dropped by dec_ttl"
> + ovs_sbx "test_dec_ttl" ip netns exec client ping -c 1 -W 2 \
> + -t 1 10.0.0.2 >/dev/null 2>&1 \
> + && { info "FAIL: ping should fail with TTL=1 and dec_ttl"
> + return 1; }
> +
> + return 0
> +}
> +
> # psample test
> # - use psample to observe packets
> test_psample() {
> diff --git a/tools/testing/selftests/net/openvswitch/ovs-dpctl.py b/tools/testing/selftests/net/openvswitch/ovs-dpctl.py
> index bbe35e2718d2..a73ca98d7aef 100644
> --- a/tools/testing/selftests/net/openvswitch/ovs-dpctl.py
> +++ b/tools/testing/selftests/net/openvswitch/ovs-dpctl.py
> @@ -388,11 +388,19 @@ class ovsactions(nla):
> ("OVS_ACTION_ATTR_CLONE", "recursive"),
> ("OVS_ACTION_ATTR_CHECK_PKT_LEN", "none"),
> ("OVS_ACTION_ATTR_ADD_MPLS", "none"),
> - ("OVS_ACTION_ATTR_DEC_TTL", "none"),
> + ("OVS_ACTION_ATTR_DEC_TTL", "DecTtl"),
> ("OVS_ACTION_ATTR_DROP", "uint32"),
> ("OVS_ACTION_ATTR_PSAMPLE", "psample"),
> )
>
> + class DecTtl(nla):
> + nla_flags = NLA_F_NESTED
> +
> + nla_map = (
> + ("OVS_DEC_TTL_ATTR_UNSPEC", "none"),
> + ("OVS_DEC_TTL_ATTR_ACTION", "actions"),
> + )
> +
> class psample(nla):
> nla_flags = NLA_F_NESTED
>
> @@ -632,6 +640,13 @@ class ovsactions(nla):
> print_str += "ct_clear"
> elif field[0] == "OVS_ACTION_ATTR_POP_VLAN":
> print_str += "pop_vlan"
> + elif field[0] == "OVS_ACTION_ATTR_DEC_TTL":
> + datum = self.get_attr(field[0])
> + print_str += "dec_ttl("
> + subacts = datum.get_attr("OVS_DEC_TTL_ATTR_ACTION")
> + if subacts and subacts.get("attrs"):
> + print_str += subacts.dpstr(more)
> + print_str += ")"
> elif field[0] == "OVS_ACTION_ATTR_POP_ETH":
> print_str += "pop_eth"
> elif field[0] == "OVS_ACTION_ATTR_POP_NSH":
> @@ -725,7 +740,21 @@ class ovsactions(nla):
> actstr = actstr[strspn(actstr, ", ") :]
> parsed = True
>
> - if parse_starts_block(actstr, "clone(", False):
> + if parse_starts_block(actstr, "dec_ttl(", False):
> + parencount += 1
> + subacts = ovsactions()
> + actstr = actstr[len("dec_ttl("):]
It looks like in odp-util.c the dec_ttl block has a defined le_1(...)
format for the TTL value being less-than-or-equal-to-1. I've CC'd Eric
since he added that parsing block.
I think it makes sense to keep that consistent with the existing ODP
utils.
> + parsedLen = subacts.parse(actstr)
> + decttl = ovsactions.DecTtl()
> + decttl["attrs"].append(
> + ("OVS_DEC_TTL_ATTR_ACTION", subacts)
> + )
> + self["attrs"].append(
> + ("OVS_ACTION_ATTR_DEC_TTL", decttl)
> + )
> + actstr = actstr[parsedLen:]
> + parsed = True
> + elif parse_starts_block(actstr, "clone(", False):
> parencount += 1
> subacts = ovsactions()
> actstr = actstr[len("clone("):]
> @@ -896,6 +925,12 @@ class ovsactions(nla):
> return (totallen - len(actstr))
>
>
> +# pyroute2 resolves nla_map types via getattr(self, name).
> +# DecTtl needs "actions" to resolve to ovsactions, but
> +# ovsactions is not defined when DecTtl class body runs.
> +ovsactions.DecTtl.actions = ovsactions
> +
> +
> class ovskey(nla):
> nla_flags = NLA_F_NESTED
> nla_map = (
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH net-next] selftests: openvswitch: add dec_ttl action support and test
2026-05-14 13:48 ` Aaron Conole
@ 2026-05-14 14:12 ` Minxi Hou
0 siblings, 0 replies; 3+ messages in thread
From: Minxi Hou @ 2026-05-14 14:12 UTC (permalink / raw)
To: Aaron Conole
Cc: Minxi Hou, netdev, davem, echaudro, edumazet, horms, i.maximets,
kuba, pabeni, shuah, dev, i.maximets, linux-kselftest,
Eric Garver
Thanks Aaron. I missed the le_1() wrapper in odp-util.c. I was only
looking at the kernel netlink attributes and derived the format from
there, which doesn't have that layer.
Will update the selftest to use dec_ttl(le_1(...)) in v2.
^ permalink raw reply [flat|nested] 3+ messages in thread
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2026-05-14 9:27 [PATCH net-next] selftests: openvswitch: add dec_ttl action support and test Minxi Hou
2026-05-14 13:48 ` Aaron Conole
2026-05-14 14:12 ` Minxi Hou
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