Re: [PATCH 4/8] man/man7/unix.7: Explain Abstract UDS scoping to the network namespace

[Kuniyuki Iwashima <kuniyu@google.com>]

On Wed, 21 Oct 2026 23:07:56 +0200, Günther Noack wrote:
> Point out that Abstract Unix Domain Sockets are visible within the
> current network namespace, unlike Named Unix Domain Sockets, where the

s/Named/pathname/.

pathname, unnamed, abstract are used in Address format section.


> remote socket is looked up through the mount namespace.
> 
> To avoid confusion, remove the word "namespace" from the subsequent
> paragraph, where it is used in a more colloquial form (there is no
> abstract socket namespace in the sense of namespaces(7)).

The change still uses "abstract socket namespace".


> 
> This is already described in network_namespaces(7) as well, but might
> be mentionworthy here too.
> 
> The lookup of Abtract addresses happens in __unix_find_socket_byname()
> in linux.git net/unix/af_unix.c, where it is looked up in the network
> namespace (struct net *net) in a hash table in that namespace:
> 
> 	sk_for_each(s, &net->unx.table.buckets[hash]) {
> 		// ...
> 	}
> 
> Cc: Kuniyuki Iwashima <kuniyu@google.com>
> Assisted-by: LLM
> Signed-off-by: Günther Noack <gnoack3000@gmail.com>
> ---
> 
> Notes:
>     Verified in code
> 
>  man/man7/unix.7 | 12 +++++++++++-
>  1 file changed, 11 insertions(+), 1 deletion(-)
> 
> diff --git a/man/man7/unix.7 b/man/man7/unix.7
> index 4c46b54206a5..232fdbf4c3cd 100644
> --- a/man/man7/unix.7
> +++ b/man/man7/unix.7
> @@ -257,7 +257,17 @@ has no effect on the accessibility of the socket.
>  Abstract sockets automatically disappear when all open references
>  to the socket are closed.
>  .P
> -The abstract socket namespace is a nonportable Linux extension.
> +Each network namespace has its own abstract socket namespace (see
> +.BR network_namespaces (7)):

Remove this sentence and...


> +a socket can connect or send to an abstract address
> +only if the socket bound to that address
> +is in the same network namespace.

add "(see network_namespaces (7))" here.


> +In contrast,
> +pathname sockets are not confined to a network namespace;
> +they can be reached from any network namespace
> +in which the socket file is accessible.
> +.P
> +Abstract sockets are a nonportable Linux extension.
>  .\"
>  .SS Socket options
>  For historical reasons, these socket options are specified with a
> -- 
> 2.56.0
>