net_dropmonitor.py

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# Monitor the system for dropped packets and proudce a report of drop locations and counts
# SPDX-License-Identifier: GPL-2.0

import os
import 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 event
def 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