/usr/share/openvswitch/scripts/ovs-check-dead-ifs is in openvswitch-switch 2.9.0-0ubuntu1.
This file is owned by root:root, with mode 0o755.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 | #! /usr/bin/python
import os
import re
import stat
import sys
if "--help" in sys.argv:
sys.stdout.write("""\
ovs-check-dead-ifs: Check for packet sockets for nonexistent network devices.
One side effect of the "force-reload-kmod" command that reloads the
Open vSwitch kernel module is that all the network devices that the
Open vSwitch kernel module implemented get destroyed and then replaced
by new instances with the same names. Unfortunately, programs that
are listening for packets on the original network devices will not
receive packets that arrive on the new instances. This causes some
services, such as DHCP, to silently fail. This program looks for such
problems and, if it finds any, prints information about programs that
are in such a state. The system administrator should then take some
action to fix the problem, such as restarting these programs.
""")
sys.exit(0)
elif len(sys.argv) > 1:
sys.stderr.write("ovs-check-dead-ifs: no arguments or options accepted "
"(use --help for help)\n")
sys.exit(1)
# Get the set of all valid ifindexes.
#
# 0 is always valid for our purposes because it means "any interface".
valid_ifindexes = set([])
for ifname in os.listdir("/sys/class/net"):
fn = "/sys/class/net/%s/ifindex" % ifname
try:
valid_ifindexes.add(int(open(fn).readline()))
except IOError:
pass
except ValueError:
print "%s: unexpected format\n" % fn
# Get inodes for all packet sockets whose ifindexes don't exist.
invalid_inodes = set()
f = open("/proc/net/packet")
f.readline() # Skip header line.
for line in f:
fields = line.split()
ifindex = int(fields[4])
if ifindex not in valid_ifindexes:
invalid_inodes.add(int(fields[8]))
f.close()
if not invalid_inodes:
sys.exit(0)
# Now find the processes that are using those packet sockets.
inode_re = re.compile(r'socket:\[([0-9]+)\]$')
bad_pids = set()
for pid in os.listdir("/proc"):
try:
pid = int(pid)
except ValueError:
continue
try:
fds = os.listdir("/proc/%d/fd" % pid)
except OSError:
continue
for fd in fds:
try:
fd = int(fd)
except ValueError:
continue
try:
s = os.stat("/proc/%d/fd/%d" % (pid, fd))
except OSError:
continue
if not stat.S_ISSOCK(s.st_mode):
continue
try:
linkname = os.readlink("/proc/%d/fd/%d" % (pid, fd))
except OSError:
continue
m = inode_re.match(linkname)
if not m:
continue
inode = int(m.group(1))
if inode in invalid_inodes:
bad_pids.add(pid)
if bad_pids:
print """
The following processes are listening for packets to arrive on network devices
that no longer exist. You may want to restart them."""
sys.stdout.flush()
os.execvp("ps", ["ps"] + ["%s" % pid for pid in bad_pids])
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