# Monitor the system for dropped packets and proudce a report of drop locations and counts# SPDX-License-Identifier: GPL-2.0 import osimport sys sys.path.append(os.environ['PERF_EXEC_PATH'] + \		'/scripts/python/Perf-Trace-Util/lib/Perf/Trace') from perf_trace_context import *from Core import *from Util import * drop_log = {}kallsyms = [] def get_kallsyms_table():	global kallsyms 	try:		f = open("/proc/kallsyms", "r")	except:		return 	for line in f:		loc = int(line.split()[0], 16)		name = line.split()[2]		kallsyms.append((loc, name))	kallsyms.sort() def get_sym(sloc):	loc = int(sloc) 	# Invariant: kallsyms[i][0] <= loc for all 0 <= i <= start	#            kallsyms[i][0] > loc for all end <= i < len(kallsyms)	start, end = -1, len(kallsyms)	while end != start + 1:		pivot = (start + end) // 2		if loc < kallsyms[pivot][0]:			end = pivot		else:			start = pivot 	# Now (start == -1 or kallsyms[start][0] <= loc)	# and (start == len(kallsyms) - 1 or loc < kallsyms[start + 1][0])	if start >= 0:		symloc, name = kallsyms[start]		return (name, loc - symloc)	else:		return (None, 0) def print_drop_table():	print "%25s %25s %25s" % ("LOCATION", "OFFSET", "COUNT")	for i in drop_log.keys():		(sym, off) = get_sym(i)		if sym == None:			sym = i		print "%25s %25s %25s" % (sym, off, drop_log[i])  def trace_begin():	print "Starting trace (Ctrl-C to dump results)" def trace_end():	print "Gathering kallsyms data"	get_kallsyms_table()	print_drop_table() # called from perf, when it finds a correspoinding eventdef skb__kfree_skb(name, context, cpu, sec, nsec, pid, comm, callchain,		   skbaddr, location, protocol):	slocation = str(location)	try:		drop_log[slocation] = drop_log[slocation] + 1	except:		drop_log[slocation] = 1