test for pcap on Raspberry

tests/test_pcap.py

@@ -0,0 +1,68 @@
+
+# test 
+
+import pcap
+import time
+
+
+ 
+class tester():    
+            
+    def findEthernetAdaptor(self):
+        self.strInterfaceName="eth0" # default, if the real is not found
+        print("Interfaces:\n" + '\n'.join(pcap.findalldevs()))
+        for i in range(0, 10):
+            strInterfaceName = pcap.ex_name("eth"+str(i))
+            if (strInterfaceName == '\\Device\\NPF_{E4B8176C-8516-4D48-88BC-85225ABCF259}'):
+                print("This is the wanted Ethernet adaptor.")
+                self.strInterfaceName="eth"+str(i)
+            print("eth"+ str(i) + " is " + strInterfaceName)
+            
+
+    def __init__(self):
+        self.nPacketsReceived = 0
+        #self.sniffer = pcap.pcap(name=None, promisc=True, immediate=True, timeout_ms=50)
+        # eth3 means: Third entry from back, in the list of interfaces, which is provided by pcap.findalldevs.
+        #  Improvement necessary: select the interface based on the name.
+        # For debugging of the interface names, we can patch the file
+        # C:\Users\uwemi\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.10_qbz5n2kfra8p0\LocalCache\local-packages\Python310\site-packages\pcap\_pcap_ex.py,
+        # in the function
+        #    def name(name: bytes) -> bytes:
+        # in the place after
+        # if i == idx:
+        #           print("index match at " + str(i) + " dev name=" + str(dev.name) + " dev.description=" + str(dev.description))
+        # This will print the description of the used interface.
+        #
+        # Patch for non-blocking read-iteration:
+        #   in _pcap.py, function def __next__(self), in the case of timeout (if n==0), we need to "raise StopIteration" instead of "continue".
+        #
+        self.findEthernetAdaptor()
+        self.sniffer = pcap.pcap(name=self.strInterfaceName, promisc=True, immediate=True, timeout_ms=10)
+        self.sniffer.setnonblock(True)
+        print("sniffer created at " + self.strInterfaceName)
+        
+    def mainfunction(self):  
+        # print("will evaluate self.sniffer")
+        for ts, pkt in self.sniffer: # attention: for using this in non-blocking manner, we need the patch described above.
+            self.nPacketsReceived+=1
+            # print('%d' % (ts)) # the time stamp
+
+    def callbackfunction(self, timestamp, pkt, *args):
+        print("the callback")
+        self.nPacketsReceived+=1
+        print("#" + str(self.nPacketsReceived) + ":" + '%d' % (timestamp)) # the time stamp
+        
+    def mainfunction_new(self):
+        # https://stackoverflow.com/questions/31305712/how-do-i-make-libpcap-pcap-loop-non-blocking
+        # Tell the sniffer to give exactly one received packet to the callback function:
+        self.sniffer.dispatch(1, self.callbackfunction, None)
+
+    def close(self):
+        self.sniffer.close()
+
+t=tester()
+for i in range(0, 10):
+    print("Loop nr " + str(i))
+    time.sleep(0.01)
+    t.mainfunction_new()
+t.close()