Commit | Line | Data |
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e61a41a4 IJ |
1 | #!/usr/bin/perl -w |
2 | use strict; | |
3 | use IO::Handle; | |
4 | ||
5 | my $us = $0; | |
6 | $us =~ s{.*/}{}; | |
7 | ||
90666d10 IJ |
8 | open DEBUG, ">/dev/null" or die $!; |
9 | ||
10 | if (@ARGV && $ARGV[0] eq '-D') { | |
11 | shift @ARGV; | |
12 | open DEBUG, ">&STDERR" or die $!; | |
13 | } | |
14 | ||
e61a41a4 IJ |
15 | die "$us: no arguments permitted\n" if @ARGV; |
16 | ||
17 | our ($monh,$monchild); | |
18 | ||
19 | our %reported; | |
20 | # no entry: not reported, does not exist | |
21 | # /ry+/: reported, entry exists | |
22 | # during processing only: | |
23 | # /r/: reported, may not still exist | |
24 | # /y+/: not reported, entry exists | |
25 | ||
26 | sub killmonitor () { | |
27 | return unless $monchild; | |
28 | kill 9, $monchild | |
29 | or warn "$us: cannot kill monitor child [$monchild]: $!\n"; | |
30 | $monchild=undef; | |
31 | close $monh; | |
32 | } | |
33 | ||
34 | END { killmonitor(); } | |
35 | ||
36 | my $restart; | |
37 | ||
38 | for (;;) { | |
39 | my $o; | |
40 | eval { | |
41 | if (!$monh) { | |
42 | killmonitor(); | |
43 | $monh = new IO::File; | |
44 | $monchild = open $monh, "-|", qw(ip -o monitor addr) | |
45 | or die "spawn monitor: $!\n"; | |
46 | sleep(1) if $restart++; | |
47 | } else { | |
48 | my $discard; | |
49 | my $got = sysread $monh, $discard, 4096; | |
50 | die "read monitor: $!\n" unless defined $got; | |
51 | die "monitor failed\n" unless $got; | |
52 | } | |
53 | $_='r' foreach values %reported; | |
90666d10 | 54 | print DEBUG "#########################################\n"; |
e61a41a4 | 55 | foreach my $ip (qw(4 6)) { |
90666d10 | 56 | print DEBUG "###### $ip:\n"; |
e61a41a4 IJ |
57 | my $addrh = new IO::File; |
58 | open $addrh, "-|", qw(ip -o), "-$ip", qw(addr show) | |
59 | or die "spawn addr $ip show: $!\n"; | |
60 | my $afstr = $ip==4 ? 'inet' : $ip==6 ? 'inet6' : die; | |
61 | while (<$addrh>) { | |
90666d10 | 62 | print DEBUG "#$_"; |
e61a41a4 | 63 | if (m{^\d+\:\s*(\S+)\s+$afstr\s+([0-9a-z.:]+)(?:/\d+)?\s}) { |
caa97633 | 64 | my $rhs=$'; #'; |
e61a41a4 | 65 | my $outline = "$ip $1 $2"; |
caa97633 IJ |
66 | # "ip -o addr show" has a ridiculous output format. In |
67 | # particular, it mixes output keywords which introduce | |
68 | # values with ones which don't, and there seems to be | |
69 | # no way to tell without knowing all the possible | |
70 | # keywords. We hope that before the \ there is nothing | |
71 | # which contains arbitrary text (specifically, which | |
72 | # might be `tentative' other than to specify IPv6 | |
73 | # tentativeness). We have to do this for IPv6 only | |
74 | # because in the IPv4 output, the interface name | |
75 | # appears here! | |
76 | next if $ip==6 && $rhs=~m{[^\\]* tentative\s}; | |
e61a41a4 IJ |
77 | $reported{$outline} .= "y"; |
78 | } else { | |
79 | chomp; | |
80 | warn "unexpected output from addr $ip show: $_\n"; | |
81 | } | |
82 | } | |
83 | my $r = close $addrh; | |
84 | die "addr $ip show failed $!\n" unless $r; | |
85 | $o = ''; | |
86 | } | |
87 | foreach my $k (keys %reported) { | |
88 | local $_ = $reported{$k}; | |
89 | if (m/^r$/) { | |
90 | $o .= "-$k\n"; | |
91 | delete $reported{$k}; | |
92 | } elsif (m/^y/) { | |
93 | $o .= "+$k\n"; | |
94 | } | |
95 | } | |
96 | }; | |
97 | if ($@) { | |
98 | print STDERR "$us: $@"; | |
99 | sleep 5; | |
100 | next; | |
101 | } | |
102 | print $o or die $!; | |
103 | STDOUT->flush or die $!; | |
104 | } |