[pylibs][ot-rfsim] enable CoAP-block and CoAP-observe; add CoAP-observe case study

ot-rfsim/script/build

@@ -50,6 +50,8 @@ OT_OPTIONS=(
     "-DOT_JOINER=ON"
     "-DOT_COAP=ON"
     "-DOT_COAPS=ON"
+    "-DOT_COAP_OBSERVE=ON"
+    "-DOT_COAP_BLOCK=ON"
     "-DOT_COMMISSIONER=ON"
     "-DOT_ECDSA=ON"
     "-DOT_NETDIAG_CLIENT=ON"

ot-rfsim/script/build_br

@@ -44,7 +44,6 @@ OTBR_OPTIONS=(
     "-DOT_BORDER_AGENT=ON"
     "-DOT_MLR=ON"
     "-DOT_UDP_FORWARD=ON"
-    "-DOT_COAP_BLOCK=ON"
     "-DOT_DNSSD_SERVER=ON"
     "-DOT_NETDATA_PUBLISHER=ON"
     "-DOT_SRP_SERVER=ON"

ot-rfsim/script/build_br_ccm

@@ -44,7 +44,6 @@ OTBR_OPTIONS=(
     "-DOT_BORDER_AGENT=ON"
     "-DOT_MLR=ON"
     "-DOT_UDP_FORWARD=ON"
-    "-DOT_COAP_BLOCK=ON"
     "-DOT_DNSSD_SERVER=ON"
     "-DOT_NETDATA_PUBLISHER=ON"
     "-DOT_SRP_SERVER=ON"

ot-rfsim/script/build_ccm

@@ -40,7 +40,6 @@ OT_OPTIONS=(
     "-DOT_BORDER_ROUTING_COUNTERS=OFF"
     "-DOT_NAT64_BORDER_ROUTING=OFF"
     "-DOT_MLR=ON"
-    "-DOT_COAP_BLOCK=OFF"
     "-DOT_DNSSD_SERVER=OFF"
     "-DOT_NETDATA_PUBLISHER=ON"
     "-DOT_SRP_SERVER=OFF"

ot-rfsim/script/build_latest

@@ -40,7 +40,6 @@ OT_OPTIONS=(
     "-DOT_BORDER_ROUTING_COUNTERS=OFF"
     "-DOT_NAT64_BORDER_ROUTING=OFF"
     "-DOT_MLR=ON"
-    "-DOT_COAP_BLOCK=OFF"
     "-DOT_DNSSD_SERVER=OFF"
     "-DOT_NETDATA_PUBLISHER=ON"
     "-DOT_SRP_SERVER=OFF"

ot-rfsim/script/build_v13

@@ -40,7 +40,6 @@ OT_OPTIONS=(
     "-DOT_BORDER_ROUTER=OFF"
     "-DOT_BORDER_ROUTING=OFF"
     "-DOT_MLR=ON"
-    "-DOT_COAP_BLOCK=OFF"
     "-DOT_DNSSD_SERVER=OFF"
     "-DOT_NETDATA_PUBLISHER=ON"
     "-DOT_SRP_SERVER=OFF"

pylibs/case_studies/coap_observe.py

@@ -0,0 +1,118 @@
+#!/usr/bin/env python3
+# Copyright (c) 2025, The OTNS Authors.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+# 1. Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in the
+#    documentation and/or other materials provided with the distribution.
+# 3. Neither the name of the copyright holder nor the
+#    names of its contributors may be used to endorse or promote products
+#    derived from this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+
+# Case study on use of CoAP observe.
+
+from otns.cli import OTNS
+from otns.cli.errors import OTNSExitedError
+
+
+def main():
+    ns = OTNS(otns_args=[])
+    ns.speed = 1000
+
+    # CoAP server
+    srv = ns.add("router")
+    ns.node_cmd(srv, "coap start")
+    ns.node_cmd(srv, "coap resource test-resource")
+    ns.node_cmd(srv, "coap set TestPayload_1")
+    srv_addr = ns.get_ipaddrs(srv, 'mleid')[0]
+
+    # CoAP client
+    cl = ns.add("router")
+    ns.node_cmd(cl, "coap start")
+
+    # form the network
+    ns.kpi_start()
+    ns.go(10)
+
+    # client sends observe request
+    ns.node_cmd(cl, f"coap observe {srv_addr} test-resource")
+    ns.go(90)
+
+    # time passes, and resource changes
+    ns.node_cmd(srv, "coap set TestPayload_2")
+    ns.go(100)
+
+    ns.node_cmd(srv, "coap set TestPayload_3")
+    ns.go(100)
+
+    ns.node_cmd(srv, "coap set TestPayload_4")
+    ns.go(100)
+
+    # now repeat the observe requests using CON type. This triggers CON notifications to be sent.
+    ns.node_cmd(cl, "coap cancel")
+    ns.go(100)
+    ns.node_cmd(cl, f"coap observe {srv_addr} test-resource con")
+    ns.go(100)
+    ns.node_cmd(srv, "coap set TestPayload_5")
+    ns.go(100)
+    ns.node_cmd(srv, "coap set TestPayload_6")
+    ns.go(100)
+    ns.node_cmd(srv, "coap set TestPayload_7")
+    ns.go(100)
+
+    # send a cancel request
+    ns.node_cmd(cl, f"coap cancel")
+    ns.go(100)
+
+    # server sends an interspersed CON notification after sending 5 NON notifications
+    ns.node_cmd(cl, f"coap observe {srv_addr} test-resource")
+    ns.go(100)
+    ns.node_cmd(srv, "coap set TestPayload_8")
+    ns.go(100)
+    ns.node_cmd(srv, "coap set TestPayload_9")
+    ns.go(100)
+    ns.node_cmd(srv, "coap set TestPayload_a")
+    ns.go(100)
+    ns.node_cmd(srv, "coap set TestPayload_b")
+    ns.go(100)
+    ns.node_cmd(srv, "coap set TestPayload_c")
+    ns.go(100)
+    ns.node_cmd(srv, "coap set TestPayload_d")  # this one will be sent CON
+    ns.go(0.001)
+    # this fast one will be NON. Note that the previous one isn't Ack'ed yet.
+    ns.node_cmd(srv, "coap set TestPayload_d2")
+    ns.go(100)
+    ns.node_cmd(srv, "coap set TestPayload_e")
+    ns.go(100)
+    ns.node_cmd(srv, "coap set TestPayload_e")
+    ns.go(100)
+
+    # observe another resource (a non-existing one)
+    ns.node_cmd(cl, f"coap observe {srv_addr} resnotfound")
+    ns.go(10)
+
+    ns.kpi_stop()
+    ns.web_display()
+
+if __name__ == '__main__':
+    try:
+        main()
+    except OTNSExitedError as ex:
+        if ex.exit_code != 0:
+            raise

pylibs/unittests/OTNSTestCase.py

@@ -83,3 +83,21 @@ def assertPings(self, pings, n, max_delay=1000, max_fails=0):
             else:
                 self.assertTrue(delay <= max_delay)
         self.assertTrue(n_fails <= max_fails)
+
+    def assertCoapMessageSent(self, src: int, type: int, code: int, dst_port: int = 5683, number_expected: int = 1, coap_msgs: list = None):
+        """
+        Verify that a CoAP message is sent from the given source node.
+        :param src: node id
+        :param type: CoAP type
+        :param code: CoAP code
+        :param dst_port: destination port number (default 5683)
+        :param number_expected: number of messages expected (default 1)
+        :param coap_msgs: optional list of CoAP messages from ns.coaps()
+        """
+        coap_msgs = self.ns.coaps() if coap_msgs == None else coap_msgs
+        number_seen = 0
+        for c in coap_msgs:
+            if c['src'] == src and c['dst_port'] == dst_port and c['code'] == code:
+                self.assertEqual(type, c['type'])
+                number_seen += 1
+        self.assertEqual(number_expected, number_seen, f"Expected number of CoAP messages is not present: src={src} type={type} code={code} dst_port={dst_port}")

pylibs/unittests/test_basic.py

@@ -1076,6 +1076,114 @@ def testBackgroundCommands(self):
         with self.assertRaises(errors.OTNSCliError):
             ns.node_cmd(nid_diag, f'abcdefgdns xquery test.example')
 
+    def testCoapObserve(self):
+        ns: OTNS = self.ns
+        ns.coaps_enable()
+
+        # see https://datatracker.ietf.org/doc/html/rfc7252#section-3
+        COAP_205_CONTENT = 69
+        COAP_404_NOT_FOUND = 132
+        COAP_CON = 0
+        COAP_NON = 1
+        COAP_ACK = 2
+
+        # CoAP server + resource setup
+        srv = ns.add("router")
+        ns.node_cmd(srv, "coap start")
+        ns.node_cmd(srv, "coap resource test-resource")
+        ns.node_cmd(srv, "coap set TestPayload_1")
+        srv_addr = ns.get_ipaddrs(srv, 'mleid')[0]
+
+        # CoAP client
+        cl = ns.add("router")
+        ns.node_cmd(cl, "coap start")
+
+        # form the network
+        ns.go(20)
+        self.assertFormPartitions(1)
+
+        # client sends NON observe request
+        ns.node_cmd(cl, f"coap observe {srv_addr} test-resource")
+        ns.go(10)
+        self.assertCoapMessageSent(src=srv, type=COAP_NON, code=COAP_205_CONTENT)
+
+        # resource changes: every change triggers a notification
+        for i in range(1, 10):
+            ns.node_cmd(srv, f"coap set TestPayload_{i}")
+            ns.go(10)
+            self.assertCoapMessageSent(src=srv, type=COAP_CON if i == 6 else COAP_NON, code=COAP_205_CONTENT)
+
+        # cancel subscription
+        ns.node_cmd(cl, "coap cancel")
+        ns.go(10)
+        self.assertCoapMessageSent(src=srv, type=COAP_ACK, code=COAP_205_CONTENT)
+
+        # now repeat the observe request using CON type. This triggers CON notifications to be sent.
+        ns.node_cmd(cl, f"coap observe {srv_addr} test-resource con")
+        ns.go(10)
+        self.assertCoapMessageSent(src=srv, type=COAP_ACK, code=COAP_205_CONTENT)
+
+        # resource changes: every change triggers a notification
+        for i in range(1, 10):
+            ns.node_cmd(srv, f"coap set TestPayload_{i}")
+            ns.go(10)
+            self.assertCoapMessageSent(src=srv, type=COAP_CON, code=COAP_205_CONTENT)
+
+        # send a cancel request again
+        ns.node_cmd(cl, f"coap cancel")
+        ns.go(10)
+        self.assertCoapMessageSent(src=srv, type=COAP_ACK, code=COAP_205_CONTENT)
+
+        # observe another resource (a non-existing one)
+        ns.node_cmd(cl, f"coap observe {srv_addr} resnotfound")
+        ns.go(10)
+        self.assertCoapMessageSent(src=srv, type=COAP_NON, code=COAP_404_NOT_FOUND)
+
+    def testCoapBlock(self):
+        ns: OTNS = self.ns
+        ns.coaps_enable()
+
+        # see https://datatracker.ietf.org/doc/html/rfc7252#section-3
+        COAP_204_CHANGED = (2 << 5) + 4
+        COAP_205_CONTENT = (2 << 5) + 5
+        COAP_231_CONTINUE = (2 << 5) + 31
+        COAP_404_NOT_FOUND = (4 << 5) + 4
+        COAP_CON = 0
+        COAP_NON = 1
+        COAP_ACK = 2
+
+        # CoAP server + resource setup
+        srv = ns.add("router")
+        ns.node_cmd(srv, "coap start")
+        ns.node_cmd(srv, "coap resource test-resource")
+        srv_addr = ns.get_ipaddrs(srv, 'mleid')[0]
+
+        # CoAP client
+        cl = ns.add("router")
+        ns.node_cmd(cl, "coap start")
+
+        # form the network
+        ns.go(20)
+        self.assertFormPartitions(1)
+
+        # client sends blockwise GET request
+        ns.node_cmd(cl, f"coap get {srv_addr} test-resource block-32")
+        ns.go(10)
+        self.assertCoapMessageSent(src=srv, type=COAP_ACK, code=COAP_205_CONTENT, number_expected=3)
+
+        # client sends blockwise PUT request
+        ns.node_cmd(cl, f"coap put {srv_addr} test-resource block-32")
+        ns.go(10)
+        ml = self.ns.coaps()
+        self.assertCoapMessageSent(src=srv, type=COAP_ACK, code=COAP_231_CONTINUE, coap_msgs=ml, number_expected=2)
+        self.assertCoapMessageSent(src=srv, type=COAP_ACK, code=COAP_204_CHANGED, coap_msgs=ml)
+
+        # client sends blockwise POST request
+        ns.node_cmd(cl, f"coap post {srv_addr} test-resource block-32")
+        ns.go(10)
+        ml = self.ns.coaps()
+        self.assertCoapMessageSent(src=srv, type=COAP_ACK, code=COAP_231_CONTINUE, coap_msgs=ml, number_expected=2)
+        self.assertCoapMessageSent(src=srv, type=COAP_ACK, code=COAP_204_CHANGED, coap_msgs=ml)
 
 if __name__ == '__main__':
     unittest.main()