draft-ietf-6man-pio-pflag is adding a new flag to the Prefix Information
Option to signal that the network can allocate a unique IPv6 prefix per
client via DHCPv6-PD (see draft-ietf-v6ops-dhcp-pd-per-device).
When ra_honor_pio_pflag is enabled, the presence of a P-flag causes
SLAAC autoconfiguration to be disabled for that particular PIO.
An automated test has been added in Android (r.android.com/3195335) to
go along with this change.
Cc: Maciej Żenczykowski <maze@xxxxxxxxxx>
Cc: Lorenzo Colitti <lorenzo@xxxxxxxxxx>
Cc: David Lamparter <equinox@xxxxxxxxxxxxxxxxxxxxx>
Cc: Simon Horman <horms@xxxxxxxxxx>
Signed-off-by: Patrick Rohr <prohr@xxxxxxxxxx>
---
Documentation/networking/ip-sysctl.rst | 14 ++++++++++++++
include/linux/ipv6.h | 1 +
include/net/addrconf.h | 10 +++++++---
net/ipv6/addrconf.c | 15 ++++++++++++++-
4 files changed, 36 insertions(+), 4 deletions(-)
diff --git a/Documentation/networking/ip-sysctl.rst b/Documentation/networking/ip-sysctl.rst
index 3616389c8c2d..eacf8983e230 100644
--- a/Documentation/networking/ip-sysctl.rst
+++ b/Documentation/networking/ip-sysctl.rst
@@ -2362,6 +2362,20 @@ ra_honor_pio_life - BOOLEAN
Default: 0 (disabled)
+ra_honor_pio_pflag - BOOLEAN
+ The Prefix Information Option P-flag indicates the network can
+ allocate a unique IPv6 prefix per client using DHCPv6-PD.
+ This sysctl can be enabled when a userspace DHCPv6-PD client
+ is running to cause the P-flag to take effect: i.e. the
+ P-flag suppresses any effects of the A-flag within the same
+ PIO. For a given PIO, P=1 and A=1 is treated as A=0.
+
+ - If disabled, the P-flag is ignored.
+ - If enabled, the P-flag will disable SLAAC autoconfiguration
+ for the given Prefix Information Option.
+
+ 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 383a0ea2ab91..a6e2aadbb91b 100644
--- a/include/linux/ipv6.h
+++ b/include/linux/ipv6.h
@@ -89,6 +89,7 @@ struct ipv6_devconf {
__u8 ioam6_enabled;
__u8 ndisc_evict_nocarrier;
__u8 ra_honor_pio_life;
+ __u8 ra_honor_pio_pflag;
struct ctl_table_header *sysctl_header;
};
diff --git a/include/net/addrconf.h b/include/net/addrconf.h
index 62a407db1bf5..b18e81f0c9e1 100644
--- a/include/net/addrconf.h
+++ b/include/net/addrconf.h
@@ -37,10 +37,14 @@ struct prefix_info {
struct __packed {
#if defined(__BIG_ENDIAN_BITFIELD)
__u8 onlink : 1,
- autoconf : 1,
- reserved : 6;
+ autoconf : 1,
+ routeraddr : 1,
+ preferpd : 1,
+ reserved : 4;
#elif defined(__LITTLE_ENDIAN_BITFIELD)
- __u8 reserved : 6,
+ __u8 reserved : 4,
+ preferpd : 1,
+ routeraddr : 1,
autoconf : 1,
onlink : 1;
#else
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 55a0fd589fc8..4febf679a435 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -239,6 +239,7 @@ static struct ipv6_devconf ipv6_devconf __read_mostly = {
.ioam6_id_wide = IOAM6_DEFAULT_IF_ID_WIDE,
.ndisc_evict_nocarrier = 1,
.ra_honor_pio_life = 0,
+ .ra_honor_pio_pflag = 0,
};
static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = {
@@ -302,6 +303,7 @@ static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = {
.ioam6_id_wide = IOAM6_DEFAULT_IF_ID_WIDE,
.ndisc_evict_nocarrier = 1,
.ra_honor_pio_life = 0,
+ .ra_honor_pio_pflag = 0,
};
/* Check if link is ready: is it up and is a valid qdisc available */
@@ -2762,6 +2764,7 @@ void addrconf_prefix_rcv(struct net_device *dev, u8 *opt, int len, bool sllao)
u32 addr_flags = 0;
struct inet6_dev *in6_dev;
struct net *net = dev_net(dev);
+ bool ignore_autoconf = false;
pinfo = (struct prefix_info *) opt;
@@ -2864,7 +2867,8 @@ void addrconf_prefix_rcv(struct net_device *dev, u8 *opt, int len, bool sllao)
/* Try to figure out our local address for this prefix */
- if (pinfo->autoconf && in6_dev->cnf.autoconf) {
+ ignore_autoconf = READ_ONCE(in6_dev->cnf.ra_honor_pio_pflag) && pinfo->preferpd;
+ if (pinfo->autoconf && in6_dev->cnf.autoconf && !ignore_autoconf) {
struct in6_addr addr;
bool tokenized = false, dev_addr_generated = false;
@@ -6926,6 +6930,15 @@ static const struct ctl_table addrconf_sysctl[] = {
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_ONE,
},
+ {
+ .procname = "ra_honor_pio_pflag",
+ .data = &ipv6_devconf.ra_honor_pio_pflag,
+ .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",
--
2.46.0.rc1.232.g9752f9e123-goog
