ip: fix possible missing trace indexes

Add safeguards when tracing packets to avoid cases where clear trace
was issue while buffers were held in reassembly.

Type: fix
Change-Id: I1bdd1e629e8bc08ce63913fd3c4b2327e47dec04
Signed-off-by: Klement Sekera <ksekera@cisco.com>

test/test_reassembly.py

@@ -170,6 +170,21 @@ class TestIPv4Reassembly(VppTestCase):
         self.verify_capture(packets)
         self.src_if.assert_nothing_captured()
 
+    def test_verify_clear_trace_mid_reassembly(self):
+        """ verify clear trace works mid-reassembly """
+
+        self.pg_enable_capture()
+        self.src_if.add_stream(self.fragments_200[0:-1])
+        self.pg_start()
+
+        self.logger.debug(self.vapi.cli("show trace"))
+        self.vapi.cli("clear trace")
+
+        self.src_if.add_stream(self.fragments_200[-1])
+        self.pg_start()
+        packets = self.dst_if.get_capture(len(self.pkt_infos))
+        self.verify_capture(packets)
+
     def test_reversed(self):
         """ reverse order reassembly """
 
@@ -588,6 +603,42 @@ class TestIPv4SVReassembly(VppTestCase):
             self.assertEqual(sent[IP].dst, recvd[IP].dst)
             self.assertEqual(sent[Raw].payload, recvd[Raw].payload)
 
+    def test_verify_clear_trace_mid_reassembly(self):
+        """ verify clear trace works mid-reassembly """
+        payload_len = 1000
+        payload = ""
+        counter = 0
+        while len(payload) < payload_len:
+            payload += "%u " % counter
+            counter += 1
+
+        p = (Ether(dst=self.src_if.local_mac, src=self.src_if.remote_mac) /
+             IP(id=1, src=self.src_if.remote_ip4,
+                dst=self.dst_if.remote_ip4) /
+             UDP(sport=1234, dport=5678) /
+             Raw(payload))
+        fragments = fragment_rfc791(p, payload_len/4)
+
+        self.pg_enable_capture()
+        self.src_if.add_stream(fragments[1])
+        self.pg_start()
+
+        self.logger.debug(self.vapi.cli("show trace"))
+        self.vapi.cli("clear trace")
+
+        self.pg_enable_capture()
+        self.src_if.add_stream(fragments[0])
+        self.pg_start()
+        self.dst_if.get_capture(2)
+
+        self.logger.debug(self.vapi.cli("show trace"))
+        self.vapi.cli("clear trace")
+
+        self.pg_enable_capture()
+        self.src_if.add_stream(fragments[2:])
+        self.pg_start()
+        self.dst_if.get_capture(len(fragments[2:]))
+
     def test_timeout(self):
         """ reassembly timeout """
         payload_len = 1000
@@ -1073,6 +1124,21 @@ class TestIPv6Reassembly(VppTestCase):
         self.src_if.assert_nothing_captured()
         self.dst_if.assert_nothing_captured()
 
+    def test_verify_clear_trace_mid_reassembly(self):
+        """ verify clear trace works mid-reassembly """
+
+        self.pg_enable_capture()
+        self.src_if.add_stream(self.fragments_400[0:-1])
+        self.pg_start()
+
+        self.logger.debug(self.vapi.cli("show trace"))
+        self.vapi.cli("clear trace")
+
+        self.src_if.add_stream(self.fragments_400[-1])
+        self.pg_start()
+        packets = self.dst_if.get_capture(len(self.pkt_infos))
+        self.verify_capture(packets)
+
     def test_reversed(self):
         """ reverse order reassembly """
 
@@ -1635,6 +1701,41 @@ class TestIPv6SVReassembly(VppTestCase):
             self.assertEqual(sent[IPv6].dst, recvd[IPv6].dst)
             self.assertEqual(sent[Raw].payload, recvd[Raw].payload)
 
+    def test_verify_clear_trace_mid_reassembly(self):
+        """ verify clear trace works mid-reassembly """
+        payload_len = 1000
+        payload = ""
+        counter = 0
+        while len(payload) < payload_len:
+            payload += "%u " % counter
+            counter += 1
+
+        p = (Ether(dst=self.src_if.local_mac, src=self.src_if.remote_mac) /
+             IPv6(src=self.src_if.remote_ip6, dst=self.dst_if.remote_ip6) /
+             UDP(sport=1234, dport=5678) /
+             Raw(payload))
+        fragments = fragment_rfc8200(p, 1, payload_len/4)
+
+        self.pg_enable_capture()
+        self.src_if.add_stream(fragments[1])
+        self.pg_start()
+
+        self.logger.debug(self.vapi.cli("show trace"))
+        self.vapi.cli("clear trace")
+
+        self.pg_enable_capture()
+        self.src_if.add_stream(fragments[0])
+        self.pg_start()
+        self.dst_if.get_capture(2)
+
+        self.logger.debug(self.vapi.cli("show trace"))
+        self.vapi.cli("clear trace")
+
+        self.pg_enable_capture()
+        self.src_if.add_stream(fragments[2:])
+        self.pg_start()
+        self.dst_if.get_capture(len(fragments[2:]))
+
     def test_timeout(self):
         """ reassembly timeout """
         payload_len = 1000