Merge branch 'net-ipv6-addrconf-ensure-that-temporary-addresses-preferred-lifetimes-are-long-enough'

Alex Henrie says:

====================
net: ipv6/addrconf: ensure that temporary addresses' preferred lifetimes are long enough

v2 corrects and updates the documentation for these features.

Changes from v1:
- Update the typical minimum lifetime stated in the documentation, and
  make it a range to emphasize the variability
- Fix spelling of "determine" in the documentation
- Mention RFC 8981's requirements in the documentation
- Arrange variables in "reverse Christmas tree"
- Update documentation of what happens if temp_prefered_lft is less
  than the minimum required lifetime

Thanks to David, Paolo, and Dan for your feedback.
====================

Link: https://lore.kernel.org/r/20240214062711.608363-1-alexhenrie24@gmail.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

1 files changed, 12 insertions, 2 deletions

diff --git a/Documentation/networking/ip-sysctl.rst b/Documentation/networking/ip-sysctl.rst
index 7afff42612e9..bd50df6a5a42 100644
--- a/Documentation/networking/ip-sysctl.rst
+++ b/Documentation/networking/ip-sysctl.rst
@@ -2503,7 +2503,7 @@ use_tempaddr - INTEGER
 
 temp_valid_lft - INTEGER
 	valid lifetime (in seconds) for temporary addresses. If less than the
-	minimum required lifetime (typically 5 seconds), temporary addresses
+	minimum required lifetime (typically 5-7 seconds), temporary addresses
 	will not be created.
 
 	Default: 172800 (2 days)
@@ -2511,7 +2511,7 @@ temp_valid_lft - INTEGER
 temp_prefered_lft - INTEGER
 	Preferred lifetime (in seconds) for temporary addresses. If
 	temp_prefered_lft is less than the minimum required lifetime (typically
-	5 seconds), temporary addresses will not be created. If
+	5-7 seconds), the preferred lifetime is the minimum required. If
 	temp_prefered_lft is greater than temp_valid_lft, the preferred lifetime
 	is temp_valid_lft.
 
@@ -2535,6 +2535,16 @@ max_desync_factor - INTEGER
 
 	Default: 600
 
+regen_min_advance - INTEGER
+	How far in advance (in seconds), at minimum, to create a new temporary
+	address before the current one is deprecated. This value is added to
+	the amount of time that may be required for duplicate address detection
+	to determine when to create a new address. Linux permits setting this
+	value to less than the default of 2 seconds, but a value less than 2
+	does not conform to RFC 8981.
+
+	Default: 2
+
 regen_max_retry - INTEGER
 	Number of attempts before give up attempting to generate
 	valid temporary addresses.