[PATCH v2 1/2] man/man2/landlock_add_rule.2: Clarify ephemeral port range

[Matthieu Buffet <matthieu@buffet.re>]

Clarify that ephemeral port range can differ from system to system, and
that an application can choose exactly which ephemeral port will be
chosen next (as long as it is within the kernel-wide
ip_local_port_range).

Signed-off-by: Matthieu Buffet <matthieu@buffet.re>
---
 man/man2/landlock_add_rule.2 | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/man/man2/landlock_add_rule.2 b/man/man2/landlock_add_rule.2
index 94bc63068935..253498bfa2cf 100644
--- a/man/man2/landlock_add_rule.2
+++ b/man/man2/landlock_add_rule.2
@@ -109,9 +109,13 @@ is the network port in host endianness.
 It should be noted that port 0 passed to
 .BR bind (2)
 will bind to an available port from the ephemeral port range.
-This can be configured in the
+The range is configured globally in the
 .I /proc/sys/net/ipv4/ip_local_port_range
-sysctl (also used for IPv6).
+sysctl (also used for IPv6),
+and can be further restricted per socket using
+.BR setsockopt (2)
+with
+.BR IP_LOCAL_PORT_RANGE (2const).
 .IP
 A Landlock rule with port 0
 and the

base-commit: c189a6b2e4dd2e74f3b360b24e489e27f4e45bad
-- 
2.47.3