From 990c304930138dcd7a49763417e6e5313b81293e Mon Sep 17 00:00:00 2001 From: Patrick Rohr Date: Mon, 29 Jul 2024 15:00:59 -0700 Subject: [PATCH] Add support for PIO p flag MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Cc: Lorenzo Colitti Cc: David Lamparter Cc: Simon Horman Signed-off-by: Patrick Rohr Reviewed-by: Maciej Żenczykowski Signed-off-by: David S. Miller --- 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 f70d8757af1a..c87d008aefa4 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",