7:48 a.m.
The 2nd patch in the series says it all; the first patch is just a typo
fix that I felt should be split off.
Thanks
Laszlo
Laszlo Ersek (2):
server/sockets: supply trailing newline for gai_strerror() format
string
server/sockets: get rid of AI_ADDRCONFIG
common/utils/windows-compat.h | 7 -------
docs/nbdkit.pod | 20 +++++++++++++++++++-
docs/synopsis.txt | 3 ++-
server/internal.h | 1 +
server/main.c | 9 +++++++++
server/options.h | 4 +++-
server/sockets.c | 5 +++--
7 files changed, 37 insertions(+), 12 deletions(-)
base-commit: 726f7f30aad14169ef878e579d9333670b5df2fa
--
2.19.1.3.g30247aa5d201
7:48 a.m.
New subject: [nbdkit PATCH 1/2] server/sockets: supply trailing newline for gai_strerror() format string
Signed-off-by: Laszlo Ersek <lersek(a)redhat.com>
---
server/sockets.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/server/sockets.c b/server/sockets.c
index edfb7428cd08..45b6b1c49110 100644
--- a/server/sockets.c
+++ b/server/sockets.c
@@ -184,7 +184,7 @@ bind_tcpip_socket (sockets *socks)
err = getaddrinfo (ipaddr, port, &hints, &ai);
if (err != 0) {
- fprintf (stderr, "%s: getaddrinfo: %s: %s: %s",
+ fprintf (stderr, "%s: getaddrinfo: %s: %s: %s\n",
program_name,
ipaddr ? ipaddr : "<any>",
port,
--
2.19.1.3.g30247aa5d201
11:07 a.m.
New subject: [nbdkit PATCH 1/2] server/sockets: supply trailing newline for gai_strerror() format string
On Tue, Jan 18, 2022 at 02:48:32PM +0100, Laszlo Ersek wrote:
Signed-off-by: Laszlo Ersek <lersek(a)redhat.com>
---
May be worth adding:
Fixes: 999797bad ("Implement nbdkit server.", v0.1.0)
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3266
Virtualization: qemu.org | libvirt.org
3:39 a.m.
New subject: [nbdkit PATCH 1/2] server/sockets: supply trailing newline for gai_strerror() format string
On 01/18/22 18:07, Eric Blake wrote:
On Tue, Jan 18, 2022 at 02:48:32PM +0100, Laszlo Ersek wrote:
> Signed-off-by: Laszlo Ersek <lersek(a)redhat.com>
> ---
May be worth adding:
Fixes: 999797bad ("Implement nbdkit server.", v0.1.0)
Will do!
Thanks,
Laszlo
7:48 a.m.
New subject: [nbdkit PATCH 2/2] server/sockets: get rid of AI_ADDRCONFIG
The AI_ADDRCONFIG hint of getaddrinfo() is supposed to restrict the name
resolution to such address families (IPv4 vs. IPv6) for which the
resolving host has publicly routable addresses assigned.
The main problem with AI_ADDRCONFIG can be shown with the following
command line:
$ nbdkit -f -p 32776 -P pidfile -i ::1 -exit-with-parent null
On a host where ::1 is the only IPv6 address assigned (namely to the
loopback interface), the command fails with
nbdkit: getaddrinfo: ::1: 32776: Address family for hostname not
supported
due to the "publicly routable" requirement.
Remove AI_ADDRCONFIG from the getaddrinfo() hints, and as a replacement,
introduce the "-4" and "-6" options, similarly to netcat and ssh.
(1) This makes options of the form:
-i 127.0.0.1
-i ::1
work regardless of "public" IPv6 / IPv4 connectivity;
(2) options of the form
-i localhost
-i FQDN
will bind both IPv4 and IPv6 addresses of the desired interface(s);
(3) omitting the option "-i" will bind both IPv4 and IPv6 wildcard
addresses (0.0.0.0 and ::);
(4) the configurations in (2) and (3) can be restricted to IPv4 or IPv6
addresses by adding the "-4" or "-6" option, respectively.
Importantly, this change allows the "connect-tcp6" test case of libnbd to
pass on such hosts that have no IPv6 connectivity (i.e., where the only
assigned IPv6 address is ::1, namely on the loopback interface).
Ref: https://listman.redhat.com/archives/libguestfs/2022-January/msg00110.html
Signed-off-by: Laszlo Ersek <lersek(a)redhat.com>
---
docs/synopsis.txt | 3 ++-
common/utils/windows-compat.h | 7 -------
server/internal.h | 1 +
server/options.h | 4 +++-
server/main.c | 9 +++++++++
server/sockets.c | 3 ++-
docs/nbdkit.pod | 20 +++++++++++++++++++-
7 files changed, 36 insertions(+), 11 deletions(-)
diff --git a/docs/synopsis.txt b/docs/synopsis.txt
index 07b9dcffe4f9..6154bb2e8805 100644
--- a/docs/synopsis.txt
+++ b/docs/synopsis.txt
@@ -1,4 +1,5 @@
-nbdkit [-D|--debug PLUGIN|FILTER|nbdkit.FLAG=N]
+nbdkit [-4|--ipv4-only] [-6|--ipv6-only]
+ [-D|--debug PLUGIN|FILTER|nbdkit.FLAG=N]
[-e|--exportname EXPORTNAME] [--exit-with-parent]
[--filter FILTER ...] [-f|--foreground]
[-g|--group GROUP] [-i|--ipaddr IPADDR]
diff --git a/common/utils/windows-compat.h b/common/utils/windows-compat.h
index 7695bf7ef7fb..658c1d8bc32b 100644
--- a/common/utils/windows-compat.h
+++ b/common/utils/windows-compat.h
@@ -75,13 +75,6 @@ struct sockaddr_un
#define O_NOCTTY 0
#endif
-/* AI_ADDRCONFIG is not available on Windows. It enables a rather
- * obscure feature of getaddrinfo to do with IPv6.
- */
-#ifndef AI_ADDRCONFIG
-#define AI_ADDRCONFIG 0
-#endif
-
/* Windows <errno.h> lacks certain errnos, so replace them here as
* best we can.
*/
diff --git a/server/internal.h b/server/internal.h
index 9e81eee629f6..f4843164025c 100644
--- a/server/internal.h
+++ b/server/internal.h
@@ -113,6 +113,7 @@ enum log_to {
LOG_TO_NULL, /* --log=null forced on the command line */
};
+extern int tcpip_sock_af;
extern struct debug_flag *debug_flags;
extern const char *export_name;
extern bool foreground;
diff --git a/server/options.h b/server/options.h
index e59ef17f90a1..39299b9d0173 100644
--- a/server/options.h
+++ b/server/options.h
@@ -59,8 +59,10 @@ enum {
VSOCK_OPTION,
};
-static const char *short_options = "D:e:fg:i:nop:P:rst:u:U:vV";
+static const char *short_options = "46D:e:fg:i:nop:P:rst:u:U:vV";
static const struct option long_options[] = {
+ { "ipv4-only", no_argument, NULL, '4' },
+ { "ipv6-only", no_argument, NULL, '6' },
{ "debug", required_argument, NULL, 'D' },
{ "dump-config", no_argument, NULL, DUMP_CONFIG_OPTION },
{ "dump-plugin", no_argument, NULL, DUMP_PLUGIN_OPTION },
diff --git a/server/main.c b/server/main.c
index 225258de710a..8e7ac149177d 100644
--- a/server/main.c
+++ b/server/main.c
@@ -86,6 +86,7 @@ static void error_if_stdio_closed (void);
static void switch_stdio (void);
static void winsock_init (void);
+int tcpip_sock_af = AF_UNSPEC; /* -4, -6 */
struct debug_flag *debug_flags; /* -D */
bool exit_with_parent; /* --exit-with-parent */
const char *export_name; /* -e */
@@ -367,6 +368,14 @@ main (int argc, char *argv[])
exit (EXIT_FAILURE);
#endif
+ case '4':
+ tcpip_sock_af = AF_INET;
+ break;
+
+ case '6':
+ tcpip_sock_af = AF_INET6;
+ break;
+
case 'D':
add_debug_flag (optarg);
break;
diff --git a/server/sockets.c b/server/sockets.c
index 45b6b1c49110..9b980a887f34 100644
--- a/server/sockets.c
+++ b/server/sockets.c
@@ -179,7 +179,8 @@ bind_tcpip_socket (sockets *socks)
port = "10809";
memset (&hints, 0, sizeof hints);
- hints.ai_flags = AI_PASSIVE | AI_ADDRCONFIG;
+ hints.ai_flags = AI_PASSIVE;
+ hints.ai_family = tcpip_sock_af;
hints.ai_socktype = SOCK_STREAM;
err = getaddrinfo (ipaddr, port, &hints, &ai);
diff --git a/docs/nbdkit.pod b/docs/nbdkit.pod
index 45a79528e2c9..009e96c8a823 100644
--- a/docs/nbdkit.pod
+++ b/docs/nbdkit.pod
@@ -173,6 +173,24 @@ Display information about nbdkit or a specific plugin:
Display brief command line usage information and exit.
+=item B<-4>
+
+=item B<--ipv4-only>
+
+=item B<-6>
+
+=item B<--ipv6-only>
+
+When a non-numeric argument is passed to the I<-i> option (such as a
+Fully Qualified Domain Name, or a host name from C</etc/hosts>),
+restrict the name resolution to IPv4 or IPv6 addresses.
+
+When the I<-i> option is omitted, listen on only the IPv4 or IPv6
+address of all interfaces (C<0.0.0.0> or C<::>, respectively).
+
+When both I<-4> and I<-6> options are present on the command line, the
+last one takes effect.
+
=item B<-D> PLUGIN.FLAG=N
=item B<-D> FILTER.FLAG=N
@@ -265,7 +283,7 @@ See also I<-u>.
=item B<--ipaddr> IPADDR
Listen on the specified interface. The default is to listen on all
-interfaces. See also I<-p>.
+interfaces. See also I<-4>, I<-6>, and I<-p>.
=item B<--log=stderr>
--
2.19.1.3.g30247aa5d201
11:19 a.m.
New subject: [nbdkit PATCH 2/2] server/sockets: get rid of AI_ADDRCONFIG
On Tue, Jan 18, 2022 at 02:48:33PM +0100, Laszlo Ersek wrote:
The AI_ADDRCONFIG hint of getaddrinfo() is supposed to restrict the
name
resolution to such address families (IPv4 vs. IPv6) for which the
resolving host has publicly routable addresses assigned.
The main problem with AI_ADDRCONFIG can be shown with the following
command line:
$ nbdkit -f -p 32776 -P pidfile -i ::1 -exit-with-parent null
s/-exit/--exit/
On a host where ::1 is the only IPv6 address assigned (namely to the
loopback interface), the command fails with
> nbdkit: getaddrinfo: ::1: 32776: Address family for hostname not
> supported
due to the "publicly routable" requirement.
Remove AI_ADDRCONFIG from the getaddrinfo() hints, and as a replacement,
introduce the "-4" and "-6" options, similarly to netcat and ssh.
Hmm, I said in my earlier reply that it may not be worth the extra
effort, but now that you've done it, it would be a shame to rip it
out.
(1) This makes options of the form:
-i 127.0.0.1
-i ::1
work regardless of "public" IPv6 / IPv4 connectivity;
(2) options of the form
-i localhost
-i FQDN
will bind both IPv4 and IPv6 addresses of the desired interface(s);
(3) omitting the option "-i" will bind both IPv4 and IPv6 wildcard
addresses (0.0.0.0 and ::);
(4) the configurations in (2) and (3) can be restricted to IPv4 or IPv6
addresses by adding the "-4" or "-6" option, respectively.
Importantly, this change allows the "connect-tcp6" test case of libnbd to
pass on such hosts that have no IPv6 connectivity (i.e., where the only
assigned IPv6 address is ::1, namely on the loopback interface).
Ref: https://listman.redhat.com/archives/libguestfs/2022-January/msg00110.html
Signed-off-by: Laszlo Ersek <lersek(a)redhat.com>
---
+++ b/server/main.c
@@ -86,6 +86,7 @@ static void error_if_stdio_closed (void);
static void switch_stdio (void);
static void winsock_init (void);
+int tcpip_sock_af = AF_UNSPEC; /* -4, -6 */
struct debug_flag *debug_flags; /* -D */
bool exit_with_parent; /* --exit-with-parent */
const char *export_name; /* -e */
@@ -367,6 +368,14 @@ main (int argc, char *argv[])
exit (EXIT_FAILURE);
#endif
+ case '4':
+ tcpip_sock_af = AF_INET;
+ break;
+
+ case '6':
+ tcpip_sock_af = AF_INET6;
+ break;
Thus, if the user uses nbdkit -46 (or -64), the last one specified
silently overrides the earlier one, rather than being diagnosed as
conflicting or explicitly permitting both. The override effect
matches the long-option naming --ipv4-only, so I can live with it, but
I'm also open to the idea of explicitly adding code to diagnose both
options at the same time as an error, if we think that's friendlier
than silent override.
+++ b/docs/nbdkit.pod
@@ -173,6 +173,24 @@ Display information about nbdkit or a specific plugin:
Display brief command line usage information and exit.
+=item B<-4>
+
+=item B<--ipv4-only>
+
+=item B<-6>
+
+=item B<--ipv6-only>
+
+When a non-numeric argument is passed to the I<-i> option (such as a
+Fully Qualified Domain Name, or a host name from C</etc/hosts>),
+restrict the name resolution to IPv4 or IPv6 addresses.
+
+When the I<-i> option is omitted, listen on only the IPv4 or IPv6
+address of all interfaces (C<0.0.0.0> or C<::>, respectively).
This effect (when -i is not used) is good justification for having
-4/-6 support.
+
+When both I<-4> and I<-6> options are present on the command line, the
+last one takes effect.
Ah, so you documented the override as intentional. It is possible to
use a git orderfile to create patches with documentation changes
appearing first in the output (see scripts/git.orderfile), which can
make it easier to review related changes in logical (rather than
alphabetical filename) order.
So with that, you have my ACK for the series, after addressing the
minor typo I spotted.
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3266
Virtualization: qemu.org | libvirt.org
5:09 a.m.
New subject: [nbdkit PATCH 2/2] server/sockets: get rid of AI_ADDRCONFIG
On 01/18/22 18:19, Eric Blake wrote:
On Tue, Jan 18, 2022 at 02:48:33PM +0100, Laszlo Ersek wrote:
> The AI_ADDRCONFIG hint of getaddrinfo() is supposed to restrict the name
> resolution to such address families (IPv4 vs. IPv6) for which the
> resolving host has publicly routable addresses assigned.
>
> The main problem with AI_ADDRCONFIG can be shown with the following
> command line:
>
> $ nbdkit -f -p 32776 -P pidfile -i ::1 -exit-with-parent null
s/-exit/--exit/
Ah yes. TBH I noticed this myself yesterday, but not in the commit
message -- in the terminal where I copied & pasted the command line
from. There must have been something up with UTF-8 and the clipboard or
whatever, because the terminal kept somehow mangling the double-dash at
the front of "--exit-with-parent". So I fixed that ultimately in the
terminal, but not in the commit message.
>
> On a host where ::1 is the only IPv6 address assigned (namely to the
> loopback interface), the command fails with
>
>> nbdkit: getaddrinfo: ::1: 32776: Address family for hostname not
>> supported
>
> due to the "publicly routable" requirement.
>
> Remove AI_ADDRCONFIG from the getaddrinfo() hints, and as a replacement,
> introduce the "-4" and "-6" options, similarly to netcat and
ssh.
Hmm, I said in my earlier reply that it may not be worth the extra
effort, but now that you've done it, it would be a shame to rip it
out.
Thanks, I feel the same way! :)
>
> (1) This makes options of the form:
>
> -i 127.0.0.1
> -i ::1
>
> work regardless of "public" IPv6 / IPv4 connectivity;
>
> (2) options of the form
>
> -i localhost
> -i FQDN
>
> will bind both IPv4 and IPv6 addresses of the desired interface(s);
>
> (3) omitting the option "-i" will bind both IPv4 and IPv6 wildcard
> addresses (0.0.0.0 and ::);
>
> (4) the configurations in (2) and (3) can be restricted to IPv4 or IPv6
> addresses by adding the "-4" or "-6" option, respectively.
>
> Importantly, this change allows the "connect-tcp6" test case of libnbd to
> pass on such hosts that have no IPv6 connectivity (i.e., where the only
> assigned IPv6 address is ::1, namely on the loopback interface).
>
> Ref: https://listman.redhat.com/archives/libguestfs/2022-January/msg00110.html
> Signed-off-by: Laszlo Ersek <lersek(a)redhat.com>
> ---
> +++ b/server/main.c
> @@ -86,6 +86,7 @@ static void error_if_stdio_closed (void);
> static void switch_stdio (void);
> static void winsock_init (void);
>
> +int tcpip_sock_af = AF_UNSPEC; /* -4, -6 */
> struct debug_flag *debug_flags; /* -D */
> bool exit_with_parent; /* --exit-with-parent */
> const char *export_name; /* -e */
> @@ -367,6 +368,14 @@ main (int argc, char *argv[])
> exit (EXIT_FAILURE);
> #endif
>
> + case '4':
> + tcpip_sock_af = AF_INET;
> + break;
> +
> + case '6':
> + tcpip_sock_af = AF_INET6;
> + break;
Thus, if the user uses nbdkit -46 (or -64), the last one specified
silently overrides the earlier one, rather than being diagnosed as
conflicting or explicitly permitting both. The override effect
matches the long-option naming --ipv4-only, so I can live with it, but
I'm also open to the idea of explicitly adding code to diagnose both
options at the same time as an error, if we think that's friendlier
than silent override.
> +++ b/docs/nbdkit.pod
> @@ -173,6 +173,24 @@ Display information about nbdkit or a specific plugin:
>
> Display brief command line usage information and exit.
>
> +=item B<-4>
> +
> +=item B<--ipv4-only>
> +
> +=item B<-6>
> +
> +=item B<--ipv6-only>
> +
> +When a non-numeric argument is passed to the I<-i> option (such as a
> +Fully Qualified Domain Name, or a host name from C</etc/hosts>),
> +restrict the name resolution to IPv4 or IPv6 addresses.
> +
> +When the I<-i> option is omitted, listen on only the IPv4 or IPv6
> +address of all interfaces (C<0.0.0.0> or C<::>, respectively).
This effect (when -i is not used) is good justification for having
-4/-6 support.
> +
> +When both I<-4> and I<-6> options are present on the command line, the
> +last one takes effect.
Ah, so you documented the override as intentional.
Yes, I had written some getopt() loops in the distant past, and
remembered this aspect.
It is possible to
use a git orderfile to create patches with documentation changes
appearing first in the output (see scripts/git.orderfile), which can
make it easier to review related changes in logical (rather than
alphabetical filename) order.
Absolutely! My top-level $HOME/.gitconfig actually sets "diff.orderFile"
to an order file I created as my "global default"; it's just that (a)
this file does not deal with *.pod files at all yet (I don't think I've
edited a POD file before), plus (b) I didn't know about
"scripts/git.orderfile" in nbdkit, and so I had not added a
"diff.orderFile" override to .git/config in my clone.
So with that, you have my ACK for the series, after addressing the
minor typo I spotted.
Thank you!
Laszlo
7:46 a.m.
New subject: [nbdkit PATCH 2/2] server/sockets: get rid of AI_ADDRCONFIG
On Tue, Jan 18, 2022 at 11:19:18AM -0600, Eric Blake wrote:
On Tue, Jan 18, 2022 at 02:48:33PM +0100, Laszlo Ersek wrote:
> + case '4':
> + tcpip_sock_af = AF_INET;
> + break;
> +
> + case '6':
> + tcpip_sock_af = AF_INET6;
> + break;
Thus, if the user uses nbdkit -46 (or -64), the last one specified
silently overrides the earlier one, rather than being diagnosed as
conflicting or explicitly permitting both. The override effect
matches the long-option naming --ipv4-only, so I can live with it, but
I'm also open to the idea of explicitly adding code to diagnose both
options at the same time as an error, if we think that's friendlier
than silent override.
Is that actually an error? -4 -6 says you want to listen on IPv4 and
IPv6 which is redundant but not wrong.
Rich.
--
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
virt-p2v converts physical machines to virtual machines. Boot with a
live CD or over the network (PXE) and turn machines into KVM guests.
http://libguestfs.org/virt-v2v
7:47 a.m.
New subject: [nbdkit PATCH 2/2] server/sockets: get rid of AI_ADDRCONFIG
On Wed, Jan 19, 2022 at 01:46:08PM +0000, Richard W.M. Jones wrote:
On Tue, Jan 18, 2022 at 11:19:18AM -0600, Eric Blake wrote:
> On Tue, Jan 18, 2022 at 02:48:33PM +0100, Laszlo Ersek wrote:
> > + case '4':
> > + tcpip_sock_af = AF_INET;
> > + break;
> > +
> > + case '6':
> > + tcpip_sock_af = AF_INET6;
> > + break;
>
> Thus, if the user uses nbdkit -46 (or -64), the last one specified
> silently overrides the earlier one, rather than being diagnosed as
> conflicting or explicitly permitting both. The override effect
> matches the long-option naming --ipv4-only, so I can live with it, but
> I'm also open to the idea of explicitly adding code to diagnose both
> options at the same time as an error, if we think that's friendlier
> than silent override.
Is that actually an error? -4 -6 says you want to listen on IPv4 and
IPv6 which is redundant but not wrong.
Oh wait, actually it doesn't work like I expected.
Is it easy to make -4 -6 listen on both IPv4 & IPv6?
Rich.
--
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
virt-df lists disk usage of guests without needing to install any
software inside the virtual machine. Supports Linux and Windows.
http://people.redhat.com/~rjones/virt-df/
9:14 a.m.
New subject: [nbdkit PATCH 2/2] server/sockets: get rid of AI_ADDRCONFIG
On 01/19/22 14:47, Richard W.M. Jones wrote:
On Wed, Jan 19, 2022 at 01:46:08PM +0000, Richard W.M. Jones wrote:
> On Tue, Jan 18, 2022 at 11:19:18AM -0600, Eric Blake wrote:
>> On Tue, Jan 18, 2022 at 02:48:33PM +0100, Laszlo Ersek wrote:
>>> + case '4':
>>> + tcpip_sock_af = AF_INET;
>>> + break;
>>> +
>>> + case '6':
>>> + tcpip_sock_af = AF_INET6;
>>> + break;
>>
>> Thus, if the user uses nbdkit -46 (or -64), the last one specified
>> silently overrides the earlier one, rather than being diagnosed as
>> conflicting or explicitly permitting both. The override effect
>> matches the long-option naming --ipv4-only, so I can live with it,
>> but I'm also open to the idea of explicitly adding code to diagnose
>> both options at the same time as an error, if we think that's
>> friendlier than silent override.
>
> Is that actually an error? -4 -6 says you want to listen on IPv4 and
> IPv6 which is redundant but not wrong.
Oh wait, actually it doesn't work like I expected.
Is it easy to make -4 -6 listen on both IPv4 & IPv6?
That's the default; in that case, just don't specify either.
-4 and -6 make AF_INET and AF_INET6 (respectively) the exclusive address
family within which the argument of option "-i" is resolved. IOW, -4 and
-6 are (intentionally) a very thin wrapper around hints.ai_family.
Here's some examples (with the "netstat -anp | grep nbdkit" output
pasted after the command line):
# most generic use: no -i, no -4, no -6: binds the wildcard address for
# both IPv4 and IPv6
$ nbdkit -f null
->
tcp 0 0 0.0.0.0:10809 0.0.0.0:* LISTEN
219346/nbdkit
tcp6 0 0 :::10809 :::* LISTEN
219346/nbdkit
# no "-i", so bind the wildcard address, but restricted to IPv4 with
# "-4"
$ nbdkit -4 -f null
->
tcp 0 0 0.0.0.0:10809 0.0.0.0:* LISTEN
219393/nbdkit
# no "-i", so bind the wildcard address, but restricted to IPv6 with
# "-6"
$ nbdkit -6 -f null
->
tcp6 0 0 :::10809 :::* LISTEN
219397/nbdkit
# "-i localhost" causes getaddrinfo() to find both the IPv4 and IPv6
# addresses (127.0.0.1 and ::1, respectively) in /etc/hosts
$ nbdkit -f -i localhost null
->
tcp 0 0 127.0.0.1:10809 0.0.0.0:* LISTEN
219386/nbdkit
tcp6 0 0 ::1:10809 :::* LISTEN
219386/nbdkit
# same as above, but "-4" restricts the resolution to IPv4
$ nbdkit -i localhost -4 -f null
->
tcp 0 0 127.0.0.1:10809 0.0.0.0:* LISTEN
219402/nbdkit
# same as above, but "-6" restricts the resolution to IPv6
$ nbdkit -i localhost -6 -f null
->
tcp6 0 0 ::1:10809 :::* LISTEN
219405/nbdkit
# "-i" is passed a numeric address, so the address family is inherent
$ nbdkit -i 127.0.0.1 -f null
->
tcp 0 0 127.0.0.1:10809 0.0.0.0:* LISTEN
219411/nbdkit
# same, but an IPv6 address is used
$ nbdkit -i ::1 -f null
->
tcp6 0 0 ::1:10809 :::* LISTEN
219414/nbdkit
# repeat the above two, with -4 / -6 restrictions, which are no-ops in
# this case
$ nbdkit -i 127.0.0.1 -4 -f null
-> tcp 0 0 127.0.0.1:10809 0.0.0.0:* LISTEN
219421/nbdkit
$ nbdkit -i ::1 -6 -f null
->
tcp6 0 0 ::1:10809 :::* LISTEN
219424/nbdkit
# We can even attempt resolving the numeric addresses for the *wrong*
# address family:
$ nbdkit -f -i 127.0.0.1 -6 null
nbdkit: getaddrinfo: 127.0.0.1: 10809: Address family for hostname not supported
$ nbdkit -f -i ::1 -4 null
nbdkit: getaddrinfo: ::1: 10809: Address family for hostname not supported
These too are correct, because the numeric address 127.0.0.1 is
unresolvable in AF_INET6, and the numeric adress ::1 is unresolvable in
AF_INET.
Thanks
Laszlo
9:16 a.m.
New subject: [nbdkit PATCH 2/2] server/sockets: get rid of AI_ADDRCONFIG
On Wed, Jan 19, 2022 at 04:14:02PM +0100, Laszlo Ersek wrote:
On 01/19/22 14:47, Richard W.M. Jones wrote:
> On Wed, Jan 19, 2022 at 01:46:08PM +0000, Richard W.M. Jones wrote:
>> On Tue, Jan 18, 2022 at 11:19:18AM -0600, Eric Blake wrote:
>>> On Tue, Jan 18, 2022 at 02:48:33PM +0100, Laszlo Ersek wrote:
>>>> + case '4':
>>>> + tcpip_sock_af = AF_INET;
>>>> + break;
>>>> +
>>>> + case '6':
>>>> + tcpip_sock_af = AF_INET6;
>>>> + break;
>>>
>>> Thus, if the user uses nbdkit -46 (or -64), the last one specified
>>> silently overrides the earlier one, rather than being diagnosed as
>>> conflicting or explicitly permitting both. The override effect
>>> matches the long-option naming --ipv4-only, so I can live with it,
>>> but I'm also open to the idea of explicitly adding code to diagnose
>>> both options at the same time as an error, if we think that's
>>> friendlier than silent override.
>>
>> Is that actually an error? -4 -6 says you want to listen on IPv4 and
>> IPv6 which is redundant but not wrong.
>
> Oh wait, actually it doesn't work like I expected.
>
> Is it easy to make -4 -6 listen on both IPv4 & IPv6?
That's the default; in that case, just don't specify either.
-4 and -6 make AF_INET and AF_INET6 (respectively) the exclusive address
family within which the argument of option "-i" is resolved. IOW, -4 and
-6 are (intentionally) a very thin wrapper around hints.ai_family.
Here's some examples (with the "netstat -anp | grep nbdkit" output
pasted after the command line):
# most generic use: no -i, no -4, no -6: binds the wildcard address for
# both IPv4 and IPv6
$ nbdkit -f null
->
tcp 0 0 0.0.0.0:10809 0.0.0.0:* LISTEN
219346/nbdkit
tcp6 0 0 :::10809 :::* LISTEN
219346/nbdkit
# no "-i", so bind the wildcard address, but restricted to IPv4 with
# "-4"
$ nbdkit -4 -f null
->
tcp 0 0 0.0.0.0:10809 0.0.0.0:* LISTEN
219393/nbdkit
# no "-i", so bind the wildcard address, but restricted to IPv6 with
# "-6"
$ nbdkit -6 -f null
->
tcp6 0 0 :::10809 :::* LISTEN
219397/nbdkit
# "-i localhost" causes getaddrinfo() to find both the IPv4 and IPv6
# addresses (127.0.0.1 and ::1, respectively) in /etc/hosts
$ nbdkit -f -i localhost null
->
tcp 0 0 127.0.0.1:10809 0.0.0.0:* LISTEN
219386/nbdkit
tcp6 0 0 ::1:10809 :::* LISTEN
219386/nbdkit
# same as above, but "-4" restricts the resolution to IPv4
$ nbdkit -i localhost -4 -f null
->
tcp 0 0 127.0.0.1:10809 0.0.0.0:* LISTEN
219402/nbdkit
# same as above, but "-6" restricts the resolution to IPv6
$ nbdkit -i localhost -6 -f null
->
tcp6 0 0 ::1:10809 :::* LISTEN
219405/nbdkit
# "-i" is passed a numeric address, so the address family is inherent
$ nbdkit -i 127.0.0.1 -f null
->
tcp 0 0 127.0.0.1:10809 0.0.0.0:* LISTEN
219411/nbdkit
# same, but an IPv6 address is used
$ nbdkit -i ::1 -f null
->
tcp6 0 0 ::1:10809 :::* LISTEN
219414/nbdkit
# repeat the above two, with -4 / -6 restrictions, which are no-ops in
# this case
$ nbdkit -i 127.0.0.1 -4 -f null
-> tcp 0 0 127.0.0.1:10809 0.0.0.0:* LISTEN
219421/nbdkit
$ nbdkit -i ::1 -6 -f null
->
tcp6 0 0 ::1:10809 :::* LISTEN
219424/nbdkit
# We can even attempt resolving the numeric addresses for the *wrong*
# address family:
$ nbdkit -f -i 127.0.0.1 -6 null
nbdkit: getaddrinfo: 127.0.0.1: 10809: Address family for hostname not supported
$ nbdkit -f -i ::1 -4 null
nbdkit: getaddrinfo: ::1: 10809: Address family for hostname not supported
These too are correct, because the numeric address 127.0.0.1 is
unresolvable in AF_INET6, and the numeric adress ::1 is unresolvable in
AF_INET.
I think it's fine as it is, thanks!
Rich.
--
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
virt-p2v converts physical machines to virtual machines. Boot with a
live CD or over the network (PXE) and turn machines into KVM guests.
http://libguestfs.org/virt-v2v
8:04 a.m.
New subject: [nbdkit PATCH 2/2] server/sockets: get rid of AI_ADDRCONFIG
On 01/19/22 14:46, Richard W.M. Jones wrote:
On Tue, Jan 18, 2022 at 11:19:18AM -0600, Eric Blake wrote:
> On Tue, Jan 18, 2022 at 02:48:33PM +0100, Laszlo Ersek wrote:
>> + case '4':
>> + tcpip_sock_af = AF_INET;
>> + break;
>> +
>> + case '6':
>> + tcpip_sock_af = AF_INET6;
>> + break;
>
> Thus, if the user uses nbdkit -46 (or -64), the last one specified
> silently overrides the earlier one, rather than being diagnosed as
> conflicting or explicitly permitting both. The override effect
> matches the long-option naming --ipv4-only, so I can live with it, but
> I'm also open to the idea of explicitly adding code to diagnose both
> options at the same time as an error, if we think that's friendlier
> than silent override.
Is that actually an error? -4 -6 says you want to listen on IPv4 and
IPv6 which is redundant but not wrong.
No, each of -4 and -6 is a restriction, not a permission, so if they
were meant to work together, the set of enabled address families would
be empty.
They simply should not be specified together. If someone still does, the
behavior is well defined, and documented. It would be possible to catch
that case and to report an error, but it's not worth the complexity.
This is pretty common with standard utilities; here's one example: the
-l (--files-with-matches) and -L (--files-without-match) flags of "grep":
mkdir x
cd x
echo a > a
echo b > b
# prints a
grep -r -l a
# prints b
grep -r -L a
# prints b, with -L taking effect
grep -r -l -L a
# prints a, with -l taking effect
grep -r -L -l a
Thanks,
Laszlo
5:42 a.m.
On 01/18/22 14:48, Laszlo Ersek wrote:
The 2nd patch in the series says it all; the first patch is just a
typo
fix that I felt should be split off.
Thanks
Laszlo
Laszlo Ersek (2):
server/sockets: supply trailing newline for gai_strerror() format
string
server/sockets: get rid of AI_ADDRCONFIG
common/utils/windows-compat.h | 7 -------
docs/nbdkit.pod | 20 +++++++++++++++++++-
docs/synopsis.txt | 3 ++-
server/internal.h | 1 +
server/main.c | 9 +++++++++
server/options.h | 4 +++-
server/sockets.c | 5 +++--
7 files changed, 37 insertions(+), 12 deletions(-)
base-commit: 726f7f30aad14169ef878e579d9333670b5df2fa
Pushed as commit range 4df525566b38..9eec2335d630, with the following
updates:
1: ee130762f9e5 ! 1: 85b653d43cac server/sockets: supply trailing
newline for gai_strerror() format string
@@ -2,7 +2,11 @@
server/sockets: supply trailing newline for gai_strerror() format string
+ Fixes: 999797bad ("Implement nbdkit server.", v0.1.0)
Signed-off-by: Laszlo Ersek <lersek(a)redhat.com>
+ Message-Id: <20220118134833.13246-2-lersek(a)redhat.com>
+ [lersek(a)redhat.com: add "Fixes:" line (Eric)]
+ Acked-by: Eric Blake <eblake(a)redhat.com>
diff --git a/server/sockets.c b/server/sockets.c
--- a/server/sockets.c
2: 499377c22999 ! 2: 9eec2335d630 server/sockets: get rid of AI_ADDRCONFIG
@@ -9,7 +9,7 @@
The main problem with AI_ADDRCONFIG can be shown with the following
command line:
- $ nbdkit -f -p 32776 -P pidfile -i ::1 -exit-with-parent null
+ $ nbdkit -f -p 32776 -P pidfile -i ::1 --exit-with-parent null
On a host where ::1 is the only IPv6 address assigned (namely to the
loopback interface), the command fails with
@@ -48,6 +48,9 @@
Ref: https://listman.redhat.com/archives/libguestfs/2022-January/msg00110.html
Signed-off-by: Laszlo Ersek <lersek(a)redhat.com>
+ Message-Id: <20220118134833.13246-3-lersek(a)redhat.com>
+ [lersek(a)redhat.com: fix typo in "--exit-with-parent" (Eric)]
+ Acked-by: Eric Blake <eblake(a)redhat.com>
diff --git a/docs/nbdkit.pod b/docs/nbdkit.pod
--- a/docs/nbdkit.pod
Thanks!
Laszlo
1038
days inactive
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days old
12 comments
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participants (3)
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Eric Blake -
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Richard W.M. Jones