Control: tag -1 + patch
Hi,
Axel Beckert wrote:
> I have more and more IPv6-only hosts. But if I add one of them to
> hosts.cfg, I always get "host not found" as error message.
>
> In the documentation under "How BackupPC Finds Hosts", it says:
>
> > First DNS is used to lookup the IP address given the client's name
> > using perl's gethostbyname() function. This should succeed for
> > machines that have fixed IP addresses that are known via DNS. You can
> > manually see whether a given host have a DNS entry according to perl's
> > gethostbyname function with this command:
> >
> > perl -e 'print(gethostbyname("myhost") ? "ok\n" : "not found\n");'
>
> Example:
>
> → host ipv6.google.com
> ipv6.google.com is an alias for ipv6.l.google.com.
> ipv6.l.google.com has IPv6 address 2a00:1450:4016:80a::200e
> $ perl -e 'print(gethostbyname("ipv6.google.com") ? "ok\n" : "not found\n");'
> not found
>
> So I can't backup this host despite SSH has no problem at all to reach
> that host.
>
> BackupPC should probably move to use Socket.pm's getaddrinfo instead as
> it is IP-version agnostic.
>
> So far I found no configuration-only workaround (i.e. disabling DNS
> lookups at all as SSH does that already.)
Ubuntu ships a patch for this for quite a while now, it is included in
e.g.
https://patches.ubuntu.com/b/backuppc/backuppc_3.3.1-4ubuntu1.patch
Relevant parts seem to me these changes:
+- (Inline) apply patch to add support for ipv6. (LP: #54918). Depend and
+ Build-Depend on libsocket6-perl for that. (LP: #1515986)
and
diff -pruN 3.3.1-4/lib/BackupPC/Config/Meta.pm
3.3.1-4ubuntu1/lib/BackupPC/Config/Meta.pm
--- 3.3.1-4/lib/BackupPC/Config/Meta.pm 2015-01-12 00:19:53.0 +
+++ 3.3.1-4ubuntu1/lib/BackupPC/Config/Meta.pm 2016-12-15 00:07:34.0
+
@@ -85,6 +85,7 @@ use vars qw(%ConfigMeta);
SshPath=> {type => "execPath", undefIfEmpty => 1},
NmbLookupPath => {type => "execPath", undefIfEmpty => 1},
PingPath => {type => "execPath", undefIfEmpty => 1},
+Ping6Path => {type => "execPath", undefIfEmpty => 1},
DfPath => {type => "execPath", undefIfEmpty => 1},
DfCmd => "string",
SplitPath => {type => "execPath", undefIfEmpty => 1},
diff -pruN 3.3.1-4/lib/BackupPC/Lib.pm 3.3.1-4ubuntu1/lib/BackupPC/Lib.pm
--- 3.3.1-4/lib/BackupPC/Lib.pm 2016-12-15 00:07:33.0 +
+++ 3.3.1-4ubuntu1/lib/BackupPC/Lib.pm 2016-12-15 00:07:34.0 +
@@ -46,6 +46,7 @@ use Carp;
use File::Path;
use File::Compare;
use Socket;
+use Socket6;
use Cwd;
use Digest::MD5;
use Config;
@@ -972,6 +973,7 @@ sub CheckHostAlive
{
my($bpc, $host) = @_;
my($s, $pingCmd, $ret);
+my($family, @res, $args);
#
# Return success if the ping cmd is undefined or empty.
@@ -982,10 +984,20 @@ sub CheckHostAlive
return 0;
}
-my $args = {
- pingPath => $bpc->{Conf}{PingPath},
- host => $host,
-};
+($family, @res) = getaddrinfo($host, "22");
+if ( $family eq AF_INET ) {
+ $args = {
+ pingPath => $bpc->{Conf}{PingPath},
+ host => $host,
+ };
+}
+if ( $family eq AF_INET6 ) {
+ $args = {
+ pingPath => $bpc->{Conf}{Ping6Path},
+ host => $host,
+ };
+}
+
$pingCmd = $bpc->cmdVarSubstitute($bpc->{Conf}{PingCmd}, $args);
#
Regards, Axel
--
,''`. | Axel Beckert , https://people.debian.org/~abe/
: :' : | Debian Developer, ftp.ch.debian.org Admin
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