On Mon, Jul 01, 2024 at 02:38:44PM GMT, Aaron Conole wrote:
> Adrian Moreno <amorenoz@xxxxxxxxxx> writes:
>
> > 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.
> >
> > Signed-off-by: Adrian Moreno <amorenoz@xxxxxxxxxx>
> > ---
> > .../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..02a366e01004 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)'
>
> Might be good to redirect this stdout/stderr line to /dev/null -
> otherwise on an unsupported system there will be the following extra
> splat:
>
> Traceback (most recent call last):
> File "/home/aconole/git/linux/tools/testing/selftests/net/openvswitch/ovs-dpctl.py", line 2774, in <module>
> sys.exit(main(sys.argv))
> ...
> File "/usr/lib/python3.12/site-packages/pyroute2/netlink/nlsocket.py", line 489, in get
> raise msg['header']['error']
> pyroute2.netlink.exceptions.NetlinkError: (22, 'Invalid argument')
>
I thought knowing the return value was kind of useful but sure, we can
redirect it to /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" $ovs_dir/s0.out >/dev/null 2>&1 || return 1
>
> I wonder if it would be better to check a few times instead of the one
> shot sleep. There are some constrained environments that may run this
> test, and if you're worried about some kinds of races, maybe it makes
> sense to check a few times?
Yes. I thought about that. There are other sleeps in this file that I
was planning to replace with a "wait_until()" function. Should we do
this as a follow-up patch to also cover the other instances?
>
> Outside of that:
>
> Reviewed-by: Aaron Conole <aconole@xxxxxxxxxx>
>
> > +
> > + # client -> server samples should only contain the first 14 bytes of the packet.
> > + grep -E "rate:4294967295,group:1,cookie:c0ffee data:[0-9a-f]{28}$" \
> > + $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 eimport 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:
>
