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authorPatrick Rohr <prohr@google.com>2023-09-25 14:47:11 -0700
committerJakub Kicinski <kuba@kernel.org>2023-10-03 15:51:04 -0700
commit473267a4911f2469722c74ca58087d951072f72a (patch)
tree08602d445874bbf990af9bb0ea03dc0f05ba38d6
parent8989682a1cb600bac1149ed17b1ce929ab472e79 (diff)
net: add sysctl to disable rfc4862 5.5.3e lifetime handling
This change adds a sysctl to opt-out of RFC4862 section 5.5.3e's valid lifetime derivation mechanism. RFC4862 section 5.5.3e prescribes that the valid lifetime in a Router Advertisement PIO shall be ignored if it less than 2 hours and to reset the lifetime of the corresponding address to 2 hours. An in-progress 6man draft (see draft-ietf-6man-slaac-renum-07 section 4.2) is currently looking to remove this mechanism. While this draft has not been moving particularly quickly for other reasons, there is widespread consensus on section 4.2 which updates RFC4862 section 5.5.3e. Cc: Maciej Żenczykowski <maze@google.com> Cc: Lorenzo Colitti <lorenzo@google.com> Cc: Jen Linkova <furry@google.com> Signed-off-by: Patrick Rohr <prohr@google.com> Reviewed-by: Jiri Pirko <jiri@nvidia.com> Reviewed-by: David Ahern <dsahern@kernel.org> Link: https://lore.kernel.org/r/20230925214711.959704-1-prohr@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
-rw-r--r--Documentation/networking/ip-sysctl.rst11
-rw-r--r--include/linux/ipv6.h1
-rw-r--r--net/ipv6/addrconf.c38
3 files changed, 37 insertions, 13 deletions
diff --git a/Documentation/networking/ip-sysctl.rst b/Documentation/networking/ip-sysctl.rst
index 5bfa1837968c..f7dfde3b09a9 100644
--- a/Documentation/networking/ip-sysctl.rst
+++ b/Documentation/networking/ip-sysctl.rst
@@ -2311,6 +2311,17 @@ accept_ra_pinfo - BOOLEAN
- enabled if accept_ra is enabled.
- disabled if accept_ra is disabled.
+ra_honor_pio_life - BOOLEAN
+ Whether to use RFC4862 Section 5.5.3e to determine the valid
+ lifetime of an address matching a prefix sent in a Router
+ Advertisement Prefix Information Option.
+
+ - If enabled, the PIO valid lifetime will always be honored.
+ - If disabled, RFC4862 section 5.5.3e is used to determine
+ the valid lifetime of the address.
+
+ Default: 0 (disabled)
+
accept_ra_rt_info_min_plen - INTEGER
Minimum prefix length of Route Information in RA.
diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h
index e400ff757f13..5e605e384aac 100644
--- a/include/linux/ipv6.h
+++ b/include/linux/ipv6.h
@@ -82,6 +82,7 @@ struct ipv6_devconf {
__u32 ioam6_id_wide;
__u8 ioam6_enabled;
__u8 ndisc_evict_nocarrier;
+ __u8 ra_honor_pio_life;
struct ctl_table_header *sysctl_header;
};
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 0b6ee962c84e..c2d471ad7922 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -236,6 +236,7 @@ static struct ipv6_devconf ipv6_devconf __read_mostly = {
.ioam6_id = IOAM6_DEFAULT_IF_ID,
.ioam6_id_wide = IOAM6_DEFAULT_IF_ID_WIDE,
.ndisc_evict_nocarrier = 1,
+ .ra_honor_pio_life = 0,
};
static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = {
@@ -297,6 +298,7 @@ static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = {
.ioam6_id = IOAM6_DEFAULT_IF_ID,
.ioam6_id_wide = IOAM6_DEFAULT_IF_ID_WIDE,
.ndisc_evict_nocarrier = 1,
+ .ra_honor_pio_life = 0,
};
/* Check if link is ready: is it up and is a valid qdisc available */
@@ -2657,22 +2659,23 @@ int addrconf_prefix_rcv_add_addr(struct net *net, struct net_device *dev,
stored_lft = ifp->valid_lft - (now - ifp->tstamp) / HZ;
else
stored_lft = 0;
- if (!create && stored_lft) {
+
+ /* RFC4862 Section 5.5.3e:
+ * "Note that the preferred lifetime of the
+ * corresponding address is always reset to
+ * the Preferred Lifetime in the received
+ * Prefix Information option, regardless of
+ * whether the valid lifetime is also reset or
+ * ignored."
+ *
+ * So we should always update prefered_lft here.
+ */
+ update_lft = !create && stored_lft;
+
+ if (update_lft && !in6_dev->cnf.ra_honor_pio_life) {
const u32 minimum_lft = min_t(u32,
stored_lft, MIN_VALID_LIFETIME);
valid_lft = max(valid_lft, minimum_lft);
-
- /* RFC4862 Section 5.5.3e:
- * "Note that the preferred lifetime of the
- * corresponding address is always reset to
- * the Preferred Lifetime in the received
- * Prefix Information option, regardless of
- * whether the valid lifetime is also reset or
- * ignored."
- *
- * So we should always update prefered_lft here.
- */
- update_lft = 1;
}
if (update_lft) {
@@ -6846,6 +6849,15 @@ static const struct ctl_table addrconf_sysctl[] = {
.mode = 0644,
.proc_handler = proc_dointvec,
},
+ {
+ .procname = "ra_honor_pio_life",
+ .data = &ipv6_devconf.ra_honor_pio_life,
+ .maxlen = sizeof(u8),
+ .mode = 0644,
+ .proc_handler = proc_dou8vec_minmax,
+ .extra1 = SYSCTL_ZERO,
+ .extra2 = SYSCTL_ONE,
+ },
#ifdef CONFIG_IPV6_ROUTER_PREF
{
.procname = "accept_ra_rtr_pref",