[PATCH v2 4/6] man/man7/unix.7: Explain Abstract UDS scoping to the network namespace

["Günther Noack" <gnoack3000@gmail.com>]

Point out that Abstract Unix Domain Sockets are visible within the
current network namespace, unlike pathname Unix Domain Sockets, where
the 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)).

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 c370b021589a..762bf0d1fe08 100644
--- a/man/man7/unix.7
+++ b/man/man7/unix.7
@@ -257,7 +257,17 @@ .SS Abstract sockets
 Abstract sockets automatically disappear when all open references
 to the socket are closed.
 .P
-The abstract socket namespace is a nonportable Linux extension.
+A socket can connect or send to an abstract address
+only if the socket bound to that address
+is in the same network namespace
+(see
+.BR network_namespaces (7)).
+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