[PATCH net-next v8 10/10] selftests: openvswitch: add psample test

Adrian Moreno
2024-07-02T09:54:47Z

Add a test to verify sampling packets via psample works.

In order to do that, create a subcommand in ovs-dpctl.py to listen to
on the psample multicast group and print samples.

Reviewed-by: Aaron Conole <aconole@redhat.com>
Tested-by: Ilya Maximets <i.maximets@ovn.org>
Signed-off-by: Adrian Moreno <amorenoz@redhat.com>
---
.../selftests/net/openvswitch/openvswitch.sh | 115 +++++++++++++++++-
.../selftests/net/openvswitch/ovs-dpctl.py | 73 ++++++++++-
2 files changed, 182 insertions(+), 6 deletions(-)

diff --git a/tools/testing/selftests/net/openvswitch/openvswitch.sh b/tools/testing/selftests/net/openvswitch/openvswitch.sh
index 15bca0708717..a33b63c6ef8f 100755
--- a/tools/testing/selftests/net/openvswitch/openvswitch.sh
+++ b/tools/testing/selftests/net/openvswitch/openvswitch.sh
@@ -20,7 +20,8 @@ tests="
nat_related_v4 ip4-nat-related: ICMP related matches work with SNAT
netlink_checks ovsnl: validate netlink attrs and settings
upcall_interfaces ovs: test the upcall interfaces
- drop_reason drop: test drop reasons are emitted"
+ drop_reason drop: test drop reasons are emitted
+ psample psample: Sampling packets with psample"

info() {
[ $VERBOSE = 0 ] || echo $*
@@ -102,12 +103,21 @@ ovs_netns_spawn_daemon() {
shift
netns=$1
shift
- info "spawning cmd: $*"
- ip netns exec $netns $* >> $ovs_dir/stdout 2>> $ovs_dir/stderr &
+ if [ "$netns" == "_default" ]; then
+ $* >> $ovs_dir/stdout 2>> $ovs_dir/stderr &
+ else
+ ip netns exec $netns $* >> $ovs_dir/stdout 2>> $ovs_dir/stderr &
+ fi
pid=$!
ovs_sbx "$sbx" on_exit "kill -TERM $pid 2>/dev/null"
}

+ovs_spawn_daemon() {
+ sbx=$1
+ shift
+ ovs_netns_spawn_daemon $sbx "_default" $*
+}
+
ovs_add_netns_and_veths () {
info "Adding netns attached: sbx:$1 dp:$2 {$3, $4, $5}"
ovs_sbx "$1" ip netns add "$3" || return 1
@@ -170,6 +180,19 @@ ovs_drop_reason_count()
return `echo "$perf_output" | grep "$pattern" | wc -l`
}

+ovs_test_flow_fails () {
+ ERR_MSG="Flow actions may not be safe on all matching packets"
+
+ PRE_TEST=$(dmesg | grep -c "${ERR_MSG}")
+ ovs_add_flow $@ &> /dev/null $@ && return 1
+ POST_TEST=$(dmesg | grep -c "${ERR_MSG}")
+
+ if [ "$PRE_TEST" == "$POST_TEST" ]; then
+ return 1
+ fi
+ return 0
+}
+
usage() {
echo
echo "$0 [OPTIONS] [TEST]..."
@@ -184,6 +207,92 @@ usage() {
exit 1
}

+
+# psample test
+# - use psample to observe packets
+test_psample() {
+ sbx_add "test_psample" || return $?
+
+ # Add a datapath with per-vport dispatching.
+ ovs_add_dp "test_psample" psample -V 2:1 || return 1
+
+ info "create namespaces"
+ ovs_add_netns_and_veths "test_psample" "psample" \
+ client c0 c1 172.31.110.10/24 -u || return 1
+ ovs_add_netns_and_veths "test_psample" "psample" \
+ server s0 s1 172.31.110.20/24 -u || return 1
+
+ # Check if psample actions can be configured.
+ ovs_add_flow "test_psample" psample \
+ 'in_port(1),eth(),eth_type(0x0806),arp()' 'psample(group=1)' &> /dev/null
+ if [ $? == 1 ]; then
+ info "no support for psample - skipping"
+ ovs_exit_sig
+ return $ksft_skip
+ fi
+
+ ovs_del_flows "test_psample" psample
+
+ # Test action verification.
+ OLDIFS=$IFS
+ IFS='*'
+ min_key='in_port(1),eth(),eth_type(0x0800),ipv4()'
+ for testcase in \
+ "cookie to large"*"psample(group=1,cookie=1615141312111009080706050403020100)" \
+ "no group with cookie"*"psample(cookie=abcd)" \
+ "no group"*"psample()";
+ do
+ set -- $testcase;
+ ovs_test_flow_fails "test_psample" psample $min_key $2
+ if [ $? == 1 ]; then
+ info "failed - $1"
+ return 1
+ fi
+ done
+ IFS=$OLDIFS
+
+ ovs_del_flows "test_psample" psample
+ # Allow ARP
+ ovs_add_flow "test_psample" psample \
+ 'in_port(1),eth(),eth_type(0x0806),arp()' '2' || return 1
+ ovs_add_flow "test_psample" psample \
+ 'in_port(2),eth(),eth_type(0x0806),arp()' '1' || return 1
+
+ # Sample first 14 bytes of all traffic.
+ ovs_add_flow "test_psample" psample \
+ "in_port(1),eth(),eth_type(0x0800),ipv4()" \
+ "trunc(14),psample(group=1,cookie=c0ffee),2"
+
+ # Sample all traffic. In this case, use a sample() action with both
+ # psample and an upcall emulating simultaneous local sampling and
+ # sFlow / IPFIX.
+ nlpid=$(grep -E "listening on upcall packet handler" \
+ $ovs_dir/s0.out | cut -d ":" -f 2 | tr -d ' ')
+
+ ovs_add_flow "test_psample" psample \
+ "in_port(2),eth(),eth_type(0x0800),ipv4()" \
+ "sample(sample=100%,actions(psample(group=2,cookie=eeff0c),userspace(pid=${nlpid},userdata=eeff0c))),1"
+
+ # Record psample data.
+ ovs_spawn_daemon "test_psample" python3 $ovs_base/ovs-dpctl.py psample-events
+
+ # Send a single ping.
+ sleep 1
+ ovs_sbx "test_psample" ip netns exec client ping -I c1 172.31.110.20 -c 1 || return 1
+ sleep 1
+
+ # We should have received one userspace action upcall and 2 psample packets.
+ grep -E "userspace action command" $ovs_dir/s0.out >/dev/null 2>&1 || return 1
+
+ # client -> server samples should only contain the first 14 bytes of the packet.
+ grep -E "rate:4294967295,group:1,cookie:c0ffee data:[0-9a-f]{28}$" \
+ $ovs_dir/stdout >/dev/null 2>&1 || return 1
+ grep -E "rate:4294967295,group:2,cookie:eeff0c" \
+ $ovs_dir/stdout >/dev/null 2>&1 || return 1
+
+ return 0
+}
+
# drop_reason test
# - drop packets and verify the right drop reason is reported
test_drop_reason() {
diff --git a/tools/testing/selftests/net/openvswitch/ovs-dpctl.py b/tools/testing/selftests/net/openvswitch/ovs-dpctl.py
index e8dc9af10d4d..1e15b0818074 100644
--- a/tools/testing/selftests/net/openvswitch/ovs-dpctl.py
+++ b/tools/testing/selftests/net/openvswitch/ovs-dpctl.py
@@ -28,8 +28,10 @@ try:
from pyroute2.netlink import genlmsg
from pyroute2.netlink import nla
from pyroute2.netlink import nlmsg_atoms
+ from pyroute2.netlink.event import EventSocket
from pyroute2.netlink.exceptions import NetlinkError
from pyroute2.netlink.generic import GenericNetlinkSocket
+ from pyroute2.netlink.nlsocket import Marshal
import pyroute2
import pyroute2.iproute

@@ -2460,10 +2462,70 @@ class OvsFlow(GenericNetlinkSocket):
print("MISS upcall[%d/%s]: %s" % (seq, pktpres, keystr), flush=True)

def execute(self, packetmsg):
- print("userspace execute command")
+ print("userspace execute command", flush=True)

def action(self, packetmsg):
- print("userspace action command")
+ print("userspace action command", flush=True)
+
+
+class psample_sample(genlmsg):
+ nla_map = (
+ ("PSAMPLE_ATTR_IIFINDEX", "none"),
+ ("PSAMPLE_ATTR_OIFINDEX", "none"),
+ ("PSAMPLE_ATTR_ORIGSIZE", "none"),
+ ("PSAMPLE_ATTR_SAMPLE_GROUP", "uint32"),
+ ("PSAMPLE_ATTR_GROUP_SEQ", "none"),
+ ("PSAMPLE_ATTR_SAMPLE_RATE", "uint32"),
+ ("PSAMPLE_ATTR_DATA", "array(uint8)"),
+ ("PSAMPLE_ATTR_GROUP_REFCOUNT", "none"),
+ ("PSAMPLE_ATTR_TUNNEL", "none"),
+ ("PSAMPLE_ATTR_PAD", "none"),
+ ("PSAMPLE_ATTR_OUT_TC", "none"),
+ ("PSAMPLE_ATTR_OUT_TC_OCC", "none"),
+ ("PSAMPLE_ATTR_LATENCY", "none"),
+ ("PSAMPLE_ATTR_TIMESTAMP", "none"),
+ ("PSAMPLE_ATTR_PROTO", "none"),
+ ("PSAMPLE_ATTR_USER_COOKIE", "array(uint8)"),
+ )
+
+ def dpstr(self):
+ fields = []
+ data = ""
+ for (attr, value) in self["attrs"]:
+ if attr == "PSAMPLE_ATTR_SAMPLE_GROUP":
+ fields.append("group:%d" % value)
+ if attr == "PSAMPLE_ATTR_SAMPLE_RATE":
+ fields.append("rate:%d" % value)
+ if attr == "PSAMPLE_ATTR_USER_COOKIE":
+ value = "".join(format(x, "02x") for x in value)
+ fields.append("cookie:%s" % value)
+ if attr == "PSAMPLE_ATTR_DATA" and len(value) > 0:
+ data = "data:%s" % "".join(format(x, "02x") for x in value)
+
+ return ("%s %s" % (",".join(fields), data)).strip()
+
+
+class psample_msg(Marshal):
+ PSAMPLE_CMD_SAMPLE = 0
+ PSAMPLE_CMD_GET_GROUP = 1
+ PSAMPLE_CMD_NEW_GROUP = 2
+ PSAMPLE_CMD_DEL_GROUP = 3
+ PSAMPLE_CMD_SET_FILTER = 4
+ msg_map = {PSAMPLE_CMD_SAMPLE: psample_sample}
+
+
+class PsampleEvent(EventSocket):
+ genl_family = "psample"
+ mcast_groups = ["packets"]
+ marshal_class = psample_msg
+
+ def read_samples(self):
+ while True:
+ try:
+ for msg in self.get():
+ print(msg.dpstr(), flush=True)
+ except NetlinkError as ne:
+ raise ne

def print_ovsdp_full(dp_lookup_rep, ifindex, ndb=NDB(), vpl=OvsVport()):
@@ -2530,7 +2592,7 @@ def main(argv):
help="Increment 'verbose' output counter.",
default=0,
)
- subparsers = parser.add_subparsers()
+ subparsers = parser.add_subparsers(dest="subcommand")

showdpcmd = subparsers.add_parser("show")
showdpcmd.add_argument(
@@ -2605,6 +2667,8 @@ def main(argv):
delfscmd = subparsers.add_parser("del-flows")
delfscmd.add_argument("flsbr", help="Datapath name")

+ subparsers.add_parser("psample-events")
+
args = parser.parse_args()

if args.verbose > 0:
@@ -2619,6 +2683,9 @@ def main(argv):

sys.setrecursionlimit(100000)

+ if args.subcommand == "psample-events":
+ PsampleEvent().read_samples()
+
if hasattr(args, "showdp"):
found = False
for iface in ndb.interfaces:
--
2.45.2