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 <acon...@redhat.com>
Tested-by: Ilya Maximets <i.maxim...@ovn.org>
Signed-off-by: Adrian Moreno <amore...@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


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