Add logic to generate global pause frames

ansible/roles/test/files/helpers/pfc_gen.py

@@ -18,32 +18,33 @@
 
 def checksum(msg):
     s = 0
-     
+
     # loop taking 2 characters at a time
     for i in range(0, len(msg), 2):
         w = ord(msg[i]) + (ord(msg[i+1]) << 8 )
         s = s + w
-     
+
     s = (s>>16) + (s & 0xffff);
     s = s + (s >> 16);
-     
+
     #complement and mask to 4 byte short
     s = ~s & 0xffff
-     
+
     return s
 
 def main():
     usage = "usage: %prog [options] arg1 arg2"
     parser = optparse.OptionParser(usage=usage)
     parser.add_option("-i", "--interface", type="string", dest="interface", help="Interface list to send packets, seperated by ','",metavar="Interface")
-    parser.add_option('-p', "--priority", type="int", dest="priority", help="PFC class enable bitmap.", metavar="Priority")
-    parser.add_option("-t", "--time", type="int", dest="time", help="Pause time in quanta for enabled class",metavar="time")
+    parser.add_option('-p', "--priority", type="int", dest="priority", help="PFC class enable bitmap.", metavar="Priority", default=-1)
+    parser.add_option("-t", "--time", type="int", dest="time", help="Pause time in quanta for global pause or enabled class",metavar="time")
     parser.add_option("-n", "--num", type="int", dest="num", help="Number of packets to be sent",metavar="number",default=1)
     parser.add_option("-r", "--rsyslog-server", type="string", dest="rsyslog_server", default="127.0.0.1", help="Rsyslog server IPv4 address",metavar="IPAddress") 
+    parser.add_option('-g', "--global", action="store_true", dest="global_pf", help="Send global pause frames (not PFC)", default=False)
     (options, args) = parser.parse_args()
 
     if options.interface is None:
-        print "Need to specify the interface to send PFC packets."
+        print "Need to specify the interface to send PFC/global pause frame packets."
         parser.print_help()
         sys.exit(1)
 
@@ -52,7 +53,14 @@ def main():
         parser.print_help()
         sys.exit(1)
 
-    if options.priority > 255 or options.time < 0:
+    if options.global_pf:
+        # Send global pause frames
+        # -p option should not be set
+        if options.priority != -1:
+            print "'-p' option is not valid when sending global pause frames ('--global' / '-g')"
+            parser.print_help()
+            sys.exit(1)
+    elif options.priority > 255 or options.priority < 0:
         print "Enable class bitmap is not valid. Need to be in range 0-255."
         parser.print_help()
         sys.exit(1)
@@ -98,29 +106,53 @@ def main():
     Time Class 7    |       0x0000          |
                     -------------------------
     """
+    """
+    Set pause frame defined fields and generate the packet
+
+    The Ethernet Frame format for pause frames is the following:
+
+    Destination MAC |   01:80:C2:00:00:01   |
+                    -------------------------
+    Source MAC      |      Station MAC      |
+                    -------------------------
+    Ethertype       |        0x8808         |
+                    -------------------------
+    OpCode          |        0x0001         |
+                    -------------------------
+    pause time      |        0x0000         |
+                    -------------------------
+    """
     src_addr = "\x01\x02\x03\x04\x05\x06" 
     dst_addr = "\x01\x80\xc2\x00\x00\x01"
-    opcode = "\x01\x01"
+    if options.global_pf:
+        opcode = "\x00\x01"
+    else:
+        opcode = "\x01\x01"
     ethertype = "\x88\x08"
-
-    class_enable = options.priority
-    class_enable_field = binascii.unhexlify(format(class_enable, '04x'))
-
-    packet = dst_addr + src_addr + ethertype + opcode + class_enable_field
-    for p in range(0,7):
-        if (class_enable & (1<<p)):
-            packet = packet + binascii.unhexlify(format(options.time, '04x'))
-        else:
-            packet = packet + "\x00\x00"
-    packetsend = packet+hex(checksum(packet))
+
+    packet = dst_addr + src_addr + ethertype + opcode
+    if options.global_pf:
+        packet = packet + binascii.unhexlify(format(options.time, '04x'))
+    else:
+        class_enable = options.priority
+        class_enable_field = binascii.unhexlify(format(class_enable, '04x'))
+
+        packet = packet + class_enable_field
+        for p in range(0,7):
+            if (class_enable & (1<<p)):
+                packet = packet + binascii.unhexlify(format(options.time, '04x'))
+            else:
+                packet = packet + "\x00\x00"
+
+    pre_str = 'GLOBAL_PF' if options.global_pf else 'PFC'
     print "Generating %s Packet(s)" % options.num
-    my_logger.debug('PFC_STORM_START')
+    my_logger.debug(pre_str + '_STORM_START')
     iteration = options.num
     while iteration > 0:
         for s in sockets:
-            s.send(packetsend)
+            s.send(packet)
         iteration -= 1
-    my_logger.debug('PFC_STORM_END')
-        
+    my_logger.debug(pre_str + '_STORM_END')
+
 if __name__ == "__main__":
     main()