Noissue - Use parameter for network interface in the check_bandwidth nagios plugin

modules/nagios/files/check_bandwidth

 #!/usr/bin/env python
 
 import os, re, subprocess, sys, socket, struct, fcntl
 
 INTERVAL = 5
 
 def format_bandwidth(bits):
   if bits >= 1000000:
     return "%.2f Mbit/s" % (bits / 1000000)
   elif bits >= 1000:
     return "%.2f kbit/s" % (bits / 1000)
   else:
     return "%.2f bit/s" % bits
 
-def getmacaddress():
+def getmacaddress(nic="eth0"):
   # See man netdevice for the request structure: it has to start with 16 bytes
   # containing the interface name, the OS will write 8 bytes after that (2 bytes
   # family name and 6 bytes actual MAC address).
   s = socket.socket()
   SIOCGIFHWADDR = 0x8927   # see man ioctl_list
-  NIC = str(sys.argv[3])

[mathias, 2017/06/07 15:27:22]

This shouldn't be an upper-case name (I think the SIOCGIFHWADDR one above is in
order to demonstrate the association with the C macro of the same name, see
https://linux.die.net/man/7/netdevice). Also it should be a parameter interface
passed on to function getmacaddress(), so that the __main__ section is the only
place referring to sys.argv 

-  return fcntl.ioctl(s.fileno(), SIOCGIFHWADDR, struct.pack("24s", NIC))[18:24]
+  return fcntl.ioctl(s.fileno(), SIOCGIFHWADDR, struct.pack("24s", nic))[18:24]
 
 if __name__ == "__main__":
   if len(sys.argv) != 4:
     script_name = os.path.basename(sys.argv[0])
     print "Usage: %s WARN CRIT NIC" % script_name
     sys.exit(0)
 
   (warn, crit) = sys.argv[1:3]
   warn = int(sys.argv[1])
   crit = int(sys.argv[2])
+  nic = str(sys.argv[3])
 
   process = subprocess.Popen(
     ["sudo", "tcpdump", "-q", "-s", "64", "-G", str(INTERVAL), "-W", "1", "-w", "-"],
     stdout=subprocess.PIPE, stderr=subprocess.PIPE)
   mac = getmacaddress()
 
   total = {"rx": 0, "tx": 0}
   http = {"rx": 0, "tx": 0}
   https = {"rx": 0, "tx": 0}
   ssh = {"rx": 0, "tx": 0}
@@ skipping 89 matching lines @@
 
   if total["rx"] >= crit or total["tx"] >= crit:
     print "CRITICAL - " + output
     sys.exit(2)
 
   if total["rx"] >= warn or total["tx"] >= warn:
     print "WARNING - " + output
     sys.exit(1)
 
   print "OK - " + output