platform: merge branch 'th/platform-routing-rules-compare'

https://gitlab.freedesktop.org/NetworkManager/NetworkManager/merge_requests/115

(cherry picked from commit c76aaa94edbfab467a3b897b071bdd44120c08b6)

8 files changed, 273 insertions, 241 deletions

diff --git a/src/devices/nm-device.c b/src/devices/nm-device.c
index d85393eb7a..253740a225 100644
--- a/src/devices/nm-device.c
+++ b/src/devices/nm-device.c
@@ -1546,8 +1546,7 @@ _set_ip_ifindex (NMDevice *self,
 		                                        priv->ip_ifindex,
 		                                        priv->ip_iface);
 
-		if (nm_platform_check_kernel_support (platform,
-		                                      NM_PLATFORM_KERNEL_SUPPORT_USER_IPV6LL))
+		if (nm_platform_kernel_support_get (NM_PLATFORM_KERNEL_SUPPORT_TYPE_USER_IPV6LL))
 			nm_platform_link_set_user_ipv6ll_enabled (platform, priv->ip_ifindex, TRUE);
 
 		if (!nm_platform_link_is_up (platform, priv->ip_ifindex))
@@ -4330,8 +4329,7 @@ realize_start_setup (NMDevice *self,
 		if (priv->firmware_version)
 			_notify (self, PROP_FIRMWARE_VERSION);
 
-		if (nm_platform_check_kernel_support (nm_device_get_platform (self),
-		                                      NM_PLATFORM_KERNEL_SUPPORT_USER_IPV6LL))
+		if (nm_platform_kernel_support_get (NM_PLATFORM_KERNEL_SUPPORT_TYPE_USER_IPV6LL))
 			priv->ipv6ll_handle = nm_platform_link_get_user_ipv6ll_enabled (nm_device_get_platform (self), priv->ifindex);
 
 		if (nm_platform_link_supports_sriov (nm_device_get_platform (self), priv->ifindex))
@@ -9234,8 +9232,7 @@ ndisc_config_changed (NMNDisc *ndisc, const NMNDiscData *rdata, guint changed_in
 		 * addresses as /128. The reason for the /128 is to prevent the kernel
 		 * from adding a prefix route for this address. */
 		ifa_flags = 0;
-		if (nm_platform_check_kernel_support (nm_device_get_platform (self),
-		                                      NM_PLATFORM_KERNEL_SUPPORT_EXTENDED_IFA_FLAGS)) {
+		if (nm_platform_kernel_support_get (NM_PLATFORM_KERNEL_SUPPORT_TYPE_EXTENDED_IFA_FLAGS)) {
 			ifa_flags |= IFA_F_NOPREFIXROUTE;
 			if (NM_IN_SET (priv->ndisc_use_tempaddr, NM_SETTING_IP6_CONFIG_PRIVACY_PREFER_TEMP_ADDR,
 			                                         NM_SETTING_IP6_CONFIG_PRIVACY_PREFER_PUBLIC_ADDR))
@@ -9267,8 +9264,7 @@ ndisc_config_changed (NMNDisc *ndisc, const NMNDiscData *rdata, guint changed_in
 		                                  rdata->routes_n,
 		                                  nm_device_get_route_table (self, AF_INET6, TRUE),
 		                                  nm_device_get_route_metric (self, AF_INET6),
-		                                  nm_platform_check_kernel_support (nm_device_get_platform (self),
-		                                                                    NM_PLATFORM_KERNEL_SUPPORT_RTA_PREF));
+		                                  nm_platform_kernel_support_get (NM_PLATFORM_KERNEL_SUPPORT_TYPE_RTA_PREF));
 		if (priv->ac_ip6_config.current) {
 			nm_ip6_config_reset_routes_ndisc ((NMIP6Config *) priv->ac_ip6_config.current,
 			                                  rdata->gateways,
@@ -9277,8 +9273,7 @@ ndisc_config_changed (NMNDisc *ndisc, const NMNDiscData *rdata, guint changed_in
 			                                  rdata->routes_n,
 			                                  nm_device_get_route_table (self, AF_INET6, TRUE),
 			                                  nm_device_get_route_metric (self, AF_INET6),
-			                                  nm_platform_check_kernel_support (nm_device_get_platform (self),
-			                                                                    NM_PLATFORM_KERNEL_SUPPORT_RTA_PREF));
+			                                  nm_platform_kernel_support_get (NM_PLATFORM_KERNEL_SUPPORT_TYPE_RTA_PREF));
 		}
 
 	}
@@ -9466,8 +9461,7 @@ addrconf6_start (NMDevice *self, NMSettingIP6ConfigPrivacy use_tempaddr)
 	priv->ndisc_use_tempaddr = use_tempaddr;
 
 	if (   NM_IN_SET (use_tempaddr, NM_SETTING_IP6_CONFIG_PRIVACY_PREFER_TEMP_ADDR, NM_SETTING_IP6_CONFIG_PRIVACY_PREFER_PUBLIC_ADDR)
-	    && !nm_platform_check_kernel_support (nm_device_get_platform (self),
-	                                          NM_PLATFORM_KERNEL_SUPPORT_EXTENDED_IFA_FLAGS)) {
+	    && !nm_platform_kernel_support_get (NM_PLATFORM_KERNEL_SUPPORT_TYPE_EXTENDED_IFA_FLAGS)) {
 		_LOGW (LOGD_IP6, "The kernel does not support extended IFA_FLAGS needed by NM for "
 		                 "IPv6 private addresses. This feature is not available");
 	}
@@ -9574,8 +9568,7 @@ set_nm_ipv6ll (NMDevice *self, gboolean enable)
 	NMDevicePrivate *priv = NM_DEVICE_GET_PRIVATE (self);
 	int ifindex = nm_device_get_ip_ifindex (self);
 
-	if (!nm_platform_check_kernel_support (nm_device_get_platform (self),
-	                                       NM_PLATFORM_KERNEL_SUPPORT_USER_IPV6LL))
+	if (!nm_platform_kernel_support_get (NM_PLATFORM_KERNEL_SUPPORT_TYPE_USER_IPV6LL))
 		return;
 
 	priv->ipv6ll_handle = enable;
diff --git a/src/nm-iface-helper.c b/src/nm-iface-helper.c
index 1ef9f5aea6..e53b446e3b 100644
--- a/src/nm-iface-helper.c
+++ b/src/nm-iface-helper.c
@@ -186,8 +186,7 @@ ndisc_config_changed (NMNDisc *ndisc, const NMNDiscData *rdata, guint changed_in
 		 * addresses as /128. The reason for the /128 is to prevent the kernel
 		 * from adding a prefix route for this address. */
 		ifa_flags = 0;
-		if (nm_platform_check_kernel_support (NM_PLATFORM_GET,
-		                                      NM_PLATFORM_KERNEL_SUPPORT_EXTENDED_IFA_FLAGS)) {
+		if (nm_platform_kernel_support_get (NM_PLATFORM_KERNEL_SUPPORT_TYPE_EXTENDED_IFA_FLAGS)) {
 			ifa_flags |= IFA_F_NOPREFIXROUTE;
 			if (NM_IN_SET (global_opt.tempaddr, NM_SETTING_IP6_CONFIG_PRIVACY_PREFER_TEMP_ADDR,
 			                                    NM_SETTING_IP6_CONFIG_PRIVACY_PREFER_PUBLIC_ADDR))
@@ -212,8 +211,7 @@ ndisc_config_changed (NMNDisc *ndisc, const NMNDiscData *rdata, guint changed_in
 		                                  rdata->routes_n,
 		                                  RT_TABLE_MAIN,
 		                                  global_opt.priority_v6,
-		                                  nm_platform_check_kernel_support (NM_PLATFORM_GET,
-		                                                                    NM_PLATFORM_KERNEL_SUPPORT_RTA_PREF));
+		                                  nm_platform_kernel_support_get (NM_PLATFORM_KERNEL_SUPPORT_TYPE_RTA_PREF));
 	}
 
 	if (changed & NM_NDISC_CONFIG_DHCP_LEVEL) {
diff --git a/src/platform/nm-fake-platform.c b/src/platform/nm-fake-platform.c
index 05f9667e97..40a85390b6 100644
--- a/src/platform/nm-fake-platform.c
+++ b/src/platform/nm-fake-platform.c
@@ -1401,6 +1401,10 @@ nm_fake_platform_class_init (NMFakePlatformClass *klass)
 {
 	GObjectClass *object_class = G_OBJECT_CLASS (klass);
 	NMPlatformClass *platform_class = NM_PLATFORM_CLASS (klass);
+	NMPlatformKernelSupportType kernel_support;
+
+	for (kernel_support = 0; kernel_support < _NM_PLATFORM_KERNEL_SUPPORT_NUM; kernel_support++)
+		_nm_platform_kernel_support_init (kernel_support, -1);
 
 	object_class->finalize = finalize;
 
diff --git a/src/platform/nm-linux-platform.c b/src/platform/nm-linux-platform.c
index 460b321bf6..d8b18a3faf 100644
--- a/src/platform/nm-linux-platform.c
+++ b/src/platform/nm-linux-platform.c
@@ -142,8 +142,6 @@ enum {
 #define __IFLA_TUN_MAX                  10
 #define IFLA_TUN_MAX (__IFLA_TUN_MAX - 1)
 
-static const gboolean RTA_PREF_SUPPORTED_AT_COMPILETIME = (RTA_MAX >= 20 /* RTA_PREF */);
-
 G_STATIC_ASSERT (RTA_MAX == (__RTA_MAX - 1));
 #define RTA_PREF                        20
 #undef  RTA_MAX
@@ -582,119 +580,6 @@ wait_for_nl_response_to_string (WaitForNlResponseResult seq_result,
 	return buf0;
 }
 
-/*****************************************************************************
- * Support IFLA_INET6_ADDR_GEN_MODE
- *****************************************************************************/
-
-static int _support_user_ipv6ll = 0;
-#define _support_user_ipv6ll_still_undecided() (G_UNLIKELY (_support_user_ipv6ll == 0))
-
-static void
-_support_user_ipv6ll_detect (struct nlattr **tb)
-{
-	gboolean supported;
-
-	nm_assert (_support_user_ipv6ll_still_undecided ());
-
-	/* IFLA_INET6_ADDR_GEN_MODE was added in kernel 3.17, dated 5 October, 2014. */
-	supported = !!tb[IFLA_INET6_ADDR_GEN_MODE];
-	_support_user_ipv6ll = supported ? 1 : -1;
-	_LOG2D ("kernel-support: IFLA_INET6_ADDR_GEN_MODE: %s",
-	        supported ? "detected" : "not detected");
-}
-
-static gboolean
-_support_user_ipv6ll_get (void)
-{
-	if (_support_user_ipv6ll_still_undecided ()) {
-		_support_user_ipv6ll = 1;
-		_LOG2D ("kernel-support: IFLA_INET6_ADDR_GEN_MODE: %s", "failed to detect; assume support");
-	}
-	return _support_user_ipv6ll >= 0;
-}
-
-/*****************************************************************************
- * extended IFA_FLAGS support
- *****************************************************************************/
-
-static int _support_kernel_extended_ifa_flags = 0;
-
-#define _support_kernel_extended_ifa_flags_still_undecided() (G_UNLIKELY (_support_kernel_extended_ifa_flags == 0))
-
-static void
-_support_kernel_extended_ifa_flags_detect (struct nl_msg *msg)
-{
-	struct nlmsghdr *msg_hdr;
-	gboolean support;
-
-	nm_assert (_support_kernel_extended_ifa_flags_still_undecided ());
-	nm_assert (msg);
-
-	msg_hdr = nlmsg_hdr (msg);
-
-	nm_assert (msg_hdr && msg_hdr->nlmsg_type == RTM_NEWADDR);
-
-	/* IFA_FLAGS is set for IPv4 and IPv6 addresses. It was added first to IPv6,
-	 * but if we encounter an IPv4 address with IFA_FLAGS, we surely have support. */
-	if (!NM_IN_SET (((struct ifaddrmsg *) nlmsg_data (msg_hdr))->ifa_family, AF_INET, AF_INET6))
-		return;
-
-	/* see if the nl_msg contains the IFA_FLAGS attribute. If it does,
-	 * we assume, that the kernel supports extended flags, IFA_F_MANAGETEMPADDR
-	 * and IFA_F_NOPREFIXROUTE for IPv6. They were added together in kernel 3.14,
-	 * dated 30 March, 2014.
-	 *
-	 * For IPv4, IFA_F_NOPREFIXROUTE was added later, but there is no easy
-	 * way to detect kernel support. */
-	support = !!nlmsg_find_attr (msg_hdr, sizeof (struct ifaddrmsg), IFA_FLAGS);
-	_support_kernel_extended_ifa_flags = support ? 1 : -1;
-	_LOG2D ("kernel-support: extended-ifa-flags: %s", support ? "detected" : "not detected");
-}
-
-static gboolean
-_support_kernel_extended_ifa_flags_get (void)
-{
-	if (_support_kernel_extended_ifa_flags_still_undecided ()) {
-		_LOG2D ("kernel-support: extended-ifa-flags: %s", "unable to detect kernel support for handling IPv6 temporary addresses. Assume support");
-		_support_kernel_extended_ifa_flags = 1;
-	}
-	return _support_kernel_extended_ifa_flags >= 0;
-}
-
-/*****************************************************************************
- * Support RTA_PREF
- *****************************************************************************/
-
-static int _support_rta_pref = 0;
-#define _support_rta_pref_still_undecided() (G_UNLIKELY (_support_rta_pref == 0))
-
-static void
-_support_rta_pref_detect (struct nlattr **tb)
-{
-	gboolean supported;
-
-	nm_assert (_support_rta_pref_still_undecided ());
-
-	/* RTA_PREF was added in kernel 4.1, dated 21 June, 2015. */
-	supported = !!tb[RTA_PREF];
-	_support_rta_pref = supported ? 1 : -1;
-	_LOG2D ("kernel-support: RTA_PREF: ability to set router preference for IPv6 routes: %s",
-	        supported ? "detected" : "not detected");
-}
-
-static gboolean
-_support_rta_pref_get (void)
-{
-	if (_support_rta_pref_still_undecided ()) {
-		/* if we couldn't detect support, we fallback on compile-time check, whether
-		 * RTA_PREF is present in the kernel headers. */
-		_support_rta_pref = RTA_PREF_SUPPORTED_AT_COMPILETIME ? 1 : -1;
-		_LOG2D ("kernel-support: RTA_PREF: ability to set router preference for IPv6 routes: %s",
-		        RTA_PREF_SUPPORTED_AT_COMPILETIME ? "assume support" : "assume no support");
-	}
-	return _support_rta_pref >= 0;
-}
-
 /******************************************************************
  * Various utilities
  ******************************************************************/
@@ -1246,8 +1131,11 @@ _parse_af_inet6 (NMPlatform *platform,
 	/* Hack to detect support addrgenmode of the kernel. We only parse
 	 * netlink messages that we receive from kernel, hence this check
 	 * is valid. */
-	if (_support_user_ipv6ll_still_undecided ())
-		_support_user_ipv6ll_detect (tb);
+	if (!_nm_platform_kernel_support_detected (NM_PLATFORM_KERNEL_SUPPORT_TYPE_USER_IPV6LL)) {
+		/* IFLA_INET6_ADDR_GEN_MODE was added in kernel 3.17, dated 5 October, 2014. */
+		_nm_platform_kernel_support_init (NM_PLATFORM_KERNEL_SUPPORT_TYPE_USER_IPV6LL,
+		                                  tb[IFLA_INET6_ADDR_GEN_MODE] ? 1 : -1);
+	}
 
 	if (tb[IFLA_INET6_ADDR_GEN_MODE]) {
 		i6_addr_gen_mode_inv = _nm_platform_uint8_inv (nla_get_u8 (tb[IFLA_INET6_ADDR_GEN_MODE]));
@@ -3371,9 +3259,13 @@ rta_multipath_done:
 	obj->ip_route.lock_mtu      = NM_FLAGS_HAS (lock, 1 << RTAX_MTU);
 
 	if (!is_v4) {
-		/* Detect support for RTA_PREF by inspecting the netlink message. */
-		if (_support_rta_pref_still_undecided ())
-			_support_rta_pref_detect (tb);
+
+		if (!_nm_platform_kernel_support_detected (NM_PLATFORM_KERNEL_SUPPORT_TYPE_RTA_PREF)) {
+			/* Detect support for RTA_PREF by inspecting the netlink message.
+			 * RTA_PREF was added in kernel 4.1, dated 21 June, 2015. */
+			_nm_platform_kernel_support_init (NM_PLATFORM_KERNEL_SUPPORT_TYPE_RTA_PREF,
+			                                  tb[RTA_PREF] ? 1 : -1);
+		}
 
 		if (tb[RTA_PREF])
 			obj->ip6_route.rt_pref = nla_get_u8 (tb[RTA_PREF]);
@@ -3510,6 +3402,16 @@ _new_from_nl_routing_rule (struct nlmsghdr *nlh, gboolean id_only)
 		props->tun_id = nla_get_be64 (tb[FRA_TUN_ID]);
 
 	if (tb[FRA_L3MDEV]) {
+
+		if (!_nm_platform_kernel_support_detected (NM_PLATFORM_KERNEL_SUPPORT_TYPE_FRA_L3MDEV)) {
+			/* support for FRA_L3MDEV was added in 96c63fa7393d0a346acfe5a91e0c7d4c7782641b,
+			 * kernel 4.8, 3 October 2017.
+			 *
+			 * We can only detect support if the attribute is present. A missing attribute
+			 * is not conclusive. */
+			_nm_platform_kernel_support_init (NM_PLATFORM_KERNEL_SUPPORT_TYPE_FRA_L3MDEV, 1);
+		}
+
 		/* actually, kernel only allows this attribute to be missing or
 		 * "1". Still, encode it as full uint8.
 		 *
@@ -3522,6 +3424,13 @@ _new_from_nl_routing_rule (struct nlmsghdr *nlh, gboolean id_only)
 	else
 		nm_assert (props->protocol == RTPROT_UNSPEC);
 
+	if (!_nm_platform_kernel_support_detected (NM_PLATFORM_KERNEL_SUPPORT_TYPE_FRA_PROTOCOL)) {
+		/* FRA_PROTOCOL was added in kernel 4.17, dated 3 June, 2018.
+		 * See commit 1b71af6053af1bd2f849e9fda4f71c1e3f145dcf. */
+		_nm_platform_kernel_support_init (NM_PLATFORM_KERNEL_SUPPORT_TYPE_FRA_PROTOCOL,
+		                                  tb[FRA_PROTOCOL] ? 1 : -1);
+	}
+
 	if (tb[FRA_IP_PROTO])
 		props->ip_proto = nla_get_u8 (tb[FRA_IP_PROTO]);
 
@@ -3532,11 +3441,33 @@ _new_from_nl_routing_rule (struct nlmsghdr *nlh, gboolean id_only)
 	nla_memcpy_checked_size (&props->sport_range, tb[FRA_SPORT_RANGE], sizeof (props->sport_range));
 	nla_memcpy_checked_size (&props->dport_range, tb[FRA_DPORT_RANGE], sizeof (props->dport_range));
 
+	if (!_nm_platform_kernel_support_detected (NM_PLATFORM_KERNEL_SUPPORT_TYPE_FRA_IP_PROTO)) {
+		/* support for FRA_IP_PROTO, FRA_SPORT_RANGE, and FRA_DPORT_RANGE was added together
+		 * by bfff4862653bb96001ab57c1edd6d03f48e5f035, kernel 4.17, 4 June 2018.
+		 *
+		 * Unfortunately, a missing attribute does not tell us anything about support.
+		 * We can only tell for sure when we have support, but not when we don't have.  */
+		if (   tb[FRA_IP_PROTO]
+		    || tb[FRA_SPORT_RANGE]
+		    || tb[FRA_DPORT_RANGE])
+			_nm_platform_kernel_support_init (NM_PLATFORM_KERNEL_SUPPORT_TYPE_FRA_IP_PROTO, 1);
+	}
+
 	G_STATIC_ASSERT_EXPR (sizeof (NMFibRuleUidRange) == 8);
 	G_STATIC_ASSERT_EXPR (G_STRUCT_OFFSET (NMFibRuleUidRange, start) == 0);
 	G_STATIC_ASSERT_EXPR (G_STRUCT_OFFSET (NMFibRuleUidRange, end) == 4);
 
 	if (tb[FRA_UID_RANGE]) {
+
+		if (!_nm_platform_kernel_support_detected (NM_PLATFORM_KERNEL_SUPPORT_TYPE_FRA_UID_RANGE)) {
+			/* support for FRA_UID_RANGE was added in 622ec2c9d52405973c9f1ca5116eb1c393adfc7d,
+			 * kernel 4.10, 19 February 2017.
+			 *
+			 * We can only detect support if the attribute is present. A missing attribute
+			 * is not conclusive. */
+			_nm_platform_kernel_support_init (NM_PLATFORM_KERNEL_SUPPORT_TYPE_FRA_UID_RANGE, 1);
+		}
+
 		nla_memcpy_checked_size (&props->uid_range, tb[FRA_UID_RANGE], sizeof (props->uid_range));
 		props->uid_range_has = TRUE;
 	}
@@ -4654,32 +4585,6 @@ sysctl_get (NMPlatform *platform, const char *pathid, int dirfd, const char *pat
 
 /*****************************************************************************/
 
-static NMPlatformKernelSupportFlags
-check_kernel_support (NMPlatform *platform,
-                      NMPlatformKernelSupportFlags request_flags)
-{
-	NMPlatformKernelSupportFlags response = 0;
-
-	nm_assert (NM_IS_LINUX_PLATFORM (platform));
-
-	if (NM_FLAGS_HAS (request_flags, NM_PLATFORM_KERNEL_SUPPORT_EXTENDED_IFA_FLAGS)) {
-		if (_support_kernel_extended_ifa_flags_get ())
-			response |= NM_PLATFORM_KERNEL_SUPPORT_EXTENDED_IFA_FLAGS;
-	}
-
-	if (NM_FLAGS_HAS (request_flags, NM_PLATFORM_KERNEL_SUPPORT_USER_IPV6LL)) {
-		if (_support_user_ipv6ll_get ())
-			response |= NM_PLATFORM_KERNEL_SUPPORT_USER_IPV6LL;
-	}
-
-	if (NM_FLAGS_HAS (request_flags, NM_PLATFORM_KERNEL_SUPPORT_RTA_PREF)) {
-		if (_support_rta_pref_get ())
-			response |= NM_PLATFORM_KERNEL_SUPPORT_RTA_PREF;
-	}
-
-	return response;
-}
-
 static void
 process_events (NMPlatform *platform)
 {
@@ -5849,9 +5754,27 @@ event_valid_msg (NMPlatform *platform, struct nl_msg *msg, gboolean handle_event
 
 	msghdr = nlmsg_hdr (msg);
 
-	if (   _support_kernel_extended_ifa_flags_still_undecided ()
-	    && msghdr->nlmsg_type == RTM_NEWADDR)
-		_support_kernel_extended_ifa_flags_detect (msg);
+	if (   !_nm_platform_kernel_support_detected (NM_PLATFORM_KERNEL_SUPPORT_TYPE_EXTENDED_IFA_FLAGS)
+	    && msghdr->nlmsg_type == RTM_NEWADDR) {
+		/* IFA_FLAGS is set for IPv4 and IPv6 addresses. It was added first to IPv6,
+		 * but if we encounter an IPv4 address with IFA_FLAGS, we surely have support. */
+		if (   nlmsg_valid_hdr (msghdr, sizeof (struct ifaddrmsg))
+		    && NM_IN_SET (((struct ifaddrmsg *) nlmsg_data (msghdr))->ifa_family,
+		                  AF_INET,
+		                  AF_INET6)) {
+			/* see if the nl_msg contains the IFA_FLAGS attribute. If it does,
+			 * we assume, that the kernel supports extended flags, IFA_F_MANAGETEMPADDR
+			 * and IFA_F_NOPREFIXROUTE for IPv6. They were added together in kernel 3.14,
+			 * dated 30 March, 2014.
+			 *
+			 * For IPv4, IFA_F_NOPREFIXROUTE was added later, but there is no easy
+			 * way to detect kernel support. */
+			_nm_platform_kernel_support_init (NM_PLATFORM_KERNEL_SUPPORT_TYPE_EXTENDED_IFA_FLAGS,
+			                                    !!nlmsg_find_attr (msghdr, sizeof (struct ifaddrmsg), IFA_FLAGS)
+			                                  ? 1
+			                                  : -1);
+		}
+	}
 
 	if (!handle_events)
 		return;
@@ -6441,7 +6364,7 @@ link_set_user_ipv6ll_enabled (NMPlatform *platform, int ifindex, gboolean enable
 	       ifindex,
 	       nm_platform_link_inet6_addrgenmode2str (mode, NULL, 0));
 
-	if (!_support_user_ipv6ll_get ()) {
+	if (!nm_platform_kernel_support_get (NM_PLATFORM_KERNEL_SUPPORT_TYPE_USER_IPV6LL)) {
 		_LOGD ("link: change %d: user-ipv6ll: not supported", ifindex);
 		return -NME_PL_OPNOTSUPP;
 	}
@@ -9085,8 +9008,6 @@ nm_linux_platform_class_init (NMLinuxPlatformClass *klass)
 	platform_class->qdisc_add = qdisc_add;
 	platform_class->tfilter_add = tfilter_add;
 
-	platform_class->check_kernel_support = check_kernel_support;
-
 	platform_class->process_events = process_events;
 }
 
diff --git a/src/platform/nm-platform.c b/src/platform/nm-platform.c
index 53ad78caf0..88508c97f7 100644
--- a/src/platform/nm-platform.c
+++ b/src/platform/nm-platform.c
@@ -119,9 +119,6 @@ typedef struct _NMPlatformPrivate {
 	bool use_udev:1;
 	bool log_with_ptr:1;
 
-	NMPlatformKernelSupportFlags support_checked;
-	NMPlatformKernelSupportFlags support_present;
-
 	guint ip4_dev_route_blacklist_check_id;
 	guint ip4_dev_route_blacklist_gc_timeout_id;
 	GHashTable *ip4_dev_route_blacklist_hash;
@@ -277,40 +274,99 @@ NM_UTILS_LOOKUP_STR_DEFINE_STATIC (_nmp_nlm_flag_to_string_lookup, NMPNlmFlags,
 
 /*****************************************************************************/
 
-NMPlatformKernelSupportFlags
-nm_platform_check_kernel_support (NMPlatform *self,
-                                  NMPlatformKernelSupportFlags request_flags)
+volatile int _nm_platform_kernel_support_state[_NM_PLATFORM_KERNEL_SUPPORT_NUM] = { };
+
+static const struct {
+	bool compile_time_default;
+	const char *name;
+	const char *desc;
+} _nm_platform_kernel_support_info[_NM_PLATFORM_KERNEL_SUPPORT_NUM] = {
+	[NM_PLATFORM_KERNEL_SUPPORT_TYPE_EXTENDED_IFA_FLAGS] = {
+		.compile_time_default = TRUE,
+		.name                 = "EXTENDED_IFA_FLAGS",
+		.desc                 = "IPv6 temporary addresses support",
+	},
+	[NM_PLATFORM_KERNEL_SUPPORT_TYPE_USER_IPV6LL] = {
+		.compile_time_default = TRUE,
+		.name                 = "USER_IPV6LL",
+		.desc                 = "IFLA_INET6_ADDR_GEN_MODE support",
+	},
+	[NM_PLATFORM_KERNEL_SUPPORT_TYPE_RTA_PREF] = {
+		.compile_time_default = (RTA_MAX >= 20 /* RTA_PREF */),
+		.name                 = "RTA_PREF",
+		.desc                 = "ability to set router preference for IPv6 routes",
+	},
+	[NM_PLATFORM_KERNEL_SUPPORT_TYPE_FRA_L3MDEV] = {
+		.compile_time_default = (FRA_MAX >= 19 /* FRA_L3MDEV */),
+		.name                 = "FRA_L3MDEV",
+		.desc                 = "FRA_L3MDEV attribute for policy routing rules",
+	},
+	[NM_PLATFORM_KERNEL_SUPPORT_TYPE_FRA_UID_RANGE] = {
+		.compile_time_default = (FRA_MAX >= 20 /* FRA_UID_RANGE */),
+		.name                 = "FRA_UID_RANGE",
+		.desc                 = "FRA_UID_RANGE attribute for policy routing rules",
+	},
+	[NM_PLATFORM_KERNEL_SUPPORT_TYPE_FRA_PROTOCOL] = {
+		.compile_time_default = (FRA_MAX >= 21 /* FRA_PROTOCOL */),
+		.name                 = "FRA_PROTOCOL",
+		.desc                 = "FRA_PROTOCOL attribute for policy routing rules",
+	},
+	[NM_PLATFORM_KERNEL_SUPPORT_TYPE_FRA_IP_PROTO] = {
+		.compile_time_default = (FRA_MAX >= 22 /* FRA_IP_PROTO */),
+		.name                 = "FRA_IP_PROTO",
+		.desc                 = "FRA_IP_PROTO, FRA_SPORT_RANGE, FRA_DPORT_RANGE attributes for policy routing rules",
+	},
+};
+
+int
+_nm_platform_kernel_support_init (NMPlatformKernelSupportType type,
+                                  int value)
 {
-	NMPlatformPrivate *priv;
+	volatile int *p_state;
+	gboolean set_default = FALSE;
 
-	_CHECK_SELF (self, klass, TRUE);
+	nm_assert (_NM_INT_NOT_NEGATIVE (type) && type < G_N_ELEMENTS (_nm_platform_kernel_support_state));
 
-	priv = NM_PLATFORM_GET_PRIVATE (self);
+	p_state = &_nm_platform_kernel_support_state[type];
 
-	/* we cache the response from subclasses and only request it once.
-	 * This probably gives better performance, but more importantly,
-	 * we are guaranteed that the answer for a certain request_flag
-	 * is always the same. */
-	if (G_UNLIKELY (!NM_FLAGS_ALL (priv->support_checked, request_flags))) {
-		NMPlatformKernelSupportFlags checked, response;
+	if (value == 0) {
+		set_default = TRUE;
+		value =   _nm_platform_kernel_support_info[type].compile_time_default
+		        ? 1
+		        : -1;
+	}
 
-		checked = request_flags & ~priv->support_checked;
-		nm_assert (checked);
+	nm_assert (NM_IN_SET (value, -1, 1));
 
-		if (klass->check_kernel_support)
-			response = klass->check_kernel_support (self, checked);
-		else {
-			/* fake platform. Pretend no support for anything. */
-			response = 0;
-		}
+	if (!g_atomic_int_compare_and_exchange (p_state, 0, value)) {
+		value = g_atomic_int_get (p_state);
+		nm_assert (NM_IN_SET (value, -1, 1));
+		return value;
+	}
+
+#undef NM_THREAD_SAFE_ON_MAIN_THREAD
+#define NM_THREAD_SAFE_ON_MAIN_THREAD 0
 
-		priv->support_checked |= checked;
-		priv->support_present = (priv->support_present & ~checked) | (response & checked);
+	if (set_default) {
+		nm_log_dbg (LOGD_PLATFORM, "platform: kernel-support for %s (%s) not detected: assume %ssupported",
+		             _nm_platform_kernel_support_info[type].name,
+		             _nm_platform_kernel_support_info[type].desc,
+		             value >= 0 ? "" : "not ");
+	} else {
+		nm_log_dbg (LOGD_PLATFORM, "platform: kernel-support for %s (%s) detected: %ssupported",
+		            _nm_platform_kernel_support_info[type].name,
+		            _nm_platform_kernel_support_info[type].desc,
+		            value >= 0 ? "" : "not ");
 	}
 
-	return priv->support_present & request_flags;
+#undef NM_THREAD_SAFE_ON_MAIN_THREAD
+#define NM_THREAD_SAFE_ON_MAIN_THREAD 1
+
+	return value;
 }
 
+/*****************************************************************************/
+
 /**
  * nm_platform_process_events:
  * @self: platform instance
@@ -3912,7 +3968,7 @@ nm_platform_ip4_address_sync (NMPlatform *self,
 	if (!known_addresses)
 		return TRUE;
 
-	ifa_flags =   nm_platform_check_kernel_support (self, NM_PLATFORM_KERNEL_SUPPORT_EXTENDED_IFA_FLAGS)
+	ifa_flags =   nm_platform_kernel_support_get (NM_PLATFORM_KERNEL_SUPPORT_TYPE_EXTENDED_IFA_FLAGS)
 	            ? IFA_F_NOPREFIXROUTE
 	            : 0;
 
@@ -4112,7 +4168,7 @@ next_plat:
 	if (!known_addresses)
 		return TRUE;
 
-	ifa_flags =   nm_platform_check_kernel_support (self, NM_PLATFORM_KERNEL_SUPPORT_EXTENDED_IFA_FLAGS)
+	ifa_flags =   nm_platform_kernel_support_get (NM_PLATFORM_KERNEL_SUPPORT_TYPE_EXTENDED_IFA_FLAGS)
 	            ? IFA_F_NOPREFIXROUTE
 	            : 0;
 
@@ -7349,6 +7405,10 @@ nm_platform_ip6_route_cmp (const NMPlatformIP6Route *a, const NMPlatformIP6Route
                                     | FIB_RULE_IIF_DETACHED \
                                     | FIB_RULE_OIF_DETACHED)
 
+#define _routing_rule_compare(cmp_type, kernel_support_type) \
+	(   (cmp_type) == NM_PLATFORM_ROUTING_RULE_CMP_TYPE_FULL \
+	 || nm_platform_kernel_support_get (kernel_support_type))
+
 void
 nm_platform_routing_rule_hash_update (const NMPlatformRoutingRule *obj,
                                       NMPlatformRoutingRuleCmpType cmp_type,
@@ -7379,7 +7439,6 @@ nm_platform_routing_rule_hash_update (const NMPlatformRoutingRule *obj,
 		/* fall-through */
 	case NM_PLATFORM_ROUTING_RULE_CMP_TYPE_FULL:
 
-
 		nm_hash_update_vals (h,
 		                     obj->addr_family,
 		                     obj->tun_id,
@@ -7398,27 +7457,42 @@ nm_platform_routing_rule_hash_update (const NMPlatformRoutingRule *obj,
 		                      ? obj->flow
 		                      : (guint32) 0u),
 		                     NM_HASH_COMBINE_BOOLS (guint8,
-		                                            obj->uid_range_has),
+		                                            (  _routing_rule_compare (cmp_type,
+		                                                                      NM_PLATFORM_KERNEL_SUPPORT_TYPE_FRA_UID_RANGE)
+		                                             ? obj->uid_range_has
+		                                             : FALSE)),
 		                     obj->suppress_prefixlen_inverse,
 		                     obj->suppress_ifgroup_inverse,
-		                     (  cmp_full
-		                      ? obj->l3mdev
-		                      : (guint8) !!obj->l3mdev),
+		                     (  _routing_rule_compare (cmp_type,
+		                                               NM_PLATFORM_KERNEL_SUPPORT_TYPE_FRA_L3MDEV)
+		                      ? (  cmp_full
+		                         ? (guint16) obj->l3mdev
+		                         : (guint16) !!obj->l3mdev)
+		                      : G_MAXUINT16),
 		                     obj->action,
 		                     obj->tos,
 		                     obj->src_len,
 		                     obj->dst_len,
-		                     obj->protocol,
-		                     obj->ip_proto);
+		                     (  _routing_rule_compare (cmp_type,
+		                                               NM_PLATFORM_KERNEL_SUPPORT_TYPE_FRA_PROTOCOL)
+		                      ? (guint16) obj->protocol
+		                      : G_MAXUINT16));
 		addr_size = nm_utils_addr_family_to_size (obj->addr_family);
 		if (cmp_full || obj->src_len > 0)
 			nm_hash_update (h, &obj->src, addr_size);
 		if (cmp_full || obj->dst_len > 0)
 			nm_hash_update (h, &obj->dst, addr_size);
-		if (cmp_full || obj->uid_range_has)
-			nm_hash_update_valp (h, &obj->uid_range);
-		nm_hash_update_valp (h, &obj->sport_range);
-		nm_hash_update_valp (h, &obj->dport_range);
+		if (_routing_rule_compare (cmp_type,
+		                           NM_PLATFORM_KERNEL_SUPPORT_TYPE_FRA_UID_RANGE)) {
+			if (cmp_full || obj->uid_range_has)
+				nm_hash_update_valp (h, &obj->uid_range);
+		}
+		if (_routing_rule_compare (cmp_type,
+		                           NM_PLATFORM_KERNEL_SUPPORT_TYPE_FRA_IP_PROTO)) {
+			nm_hash_update_val (h, obj->ip_proto);
+			nm_hash_update_valp (h, &obj->sport_range);
+			nm_hash_update_valp (h, &obj->dport_range);
+		}
 		nm_hash_update_str (h, obj->iifname);
 		nm_hash_update_str (h, obj->oifname);
 		return;
@@ -7469,13 +7543,15 @@ nm_platform_routing_rule_cmp (const NMPlatformRoutingRule *a,
 		NM_CMP_FIELD (a, b, priority);
 		NM_CMP_FIELD (a, b, tun_id);
 
-		if (cmp_full)
-			NM_CMP_FIELD (a, b, l3mdev);
-		else
-			NM_CMP_FIELD_BOOL (a, b, l3mdev);
+		if (_routing_rule_compare (cmp_type,
+		                           NM_PLATFORM_KERNEL_SUPPORT_TYPE_FRA_L3MDEV)) {
+			if (cmp_full)
+				NM_CMP_FIELD (a, b, l3mdev);
+			else
+				NM_CMP_FIELD_BOOL (a, b, l3mdev);
+		}
 
-		if (cmp_full || !a->l3mdev)
-			NM_CMP_FIELD (a, b, table);
+		NM_CMP_FIELD (a, b, table);
 
 		NM_CMP_DIRECT (a->flags & flags_mask, b->flags & flags_mask);
 
@@ -7494,8 +7570,19 @@ nm_platform_routing_rule_cmp (const NMPlatformRoutingRule *a,
 		if (cmp_full || a->addr_family == AF_INET)
 			NM_CMP_FIELD (a, b, flow);
 
-		NM_CMP_FIELD (a, b, protocol);
-		NM_CMP_FIELD (a, b, ip_proto);
+		if (_routing_rule_compare (cmp_type,
+		                           NM_PLATFORM_KERNEL_SUPPORT_TYPE_FRA_PROTOCOL))
+			NM_CMP_FIELD (a, b, protocol);
+
+		if (_routing_rule_compare (cmp_type,
+		                           NM_PLATFORM_KERNEL_SUPPORT_TYPE_FRA_IP_PROTO)) {
+			NM_CMP_FIELD (a, b, ip_proto);
+			NM_CMP_FIELD (a, b, sport_range.start);
+			NM_CMP_FIELD (a, b, sport_range.end);
+			NM_CMP_FIELD (a, b, dport_range.start);
+			NM_CMP_FIELD (a, b, dport_range.end);
+		}
+
 		addr_size = nm_utils_addr_family_to_size (a->addr_family);
 
 		NM_CMP_FIELD (a, b, src_len);
@@ -7506,16 +7593,15 @@ nm_platform_routing_rule_cmp (const NMPlatformRoutingRule *a,
 		if (cmp_full || a->dst_len > 0)
 			NM_CMP_FIELD_MEMCMP_LEN (a, b, dst, addr_size);
 
-		NM_CMP_FIELD_UNSAFE (a, b, uid_range_has);
-		if (cmp_full || a->uid_range_has) {
-			NM_CMP_FIELD (a, b, uid_range.start);
-			NM_CMP_FIELD (a, b, uid_range.end);
+		if (_routing_rule_compare (cmp_type,
+		                           NM_PLATFORM_KERNEL_SUPPORT_TYPE_FRA_UID_RANGE)) {
+			NM_CMP_FIELD_UNSAFE (a, b, uid_range_has);
+			if (cmp_full || a->uid_range_has) {
+				NM_CMP_FIELD (a, b, uid_range.start);
+				NM_CMP_FIELD (a, b, uid_range.end);
+			}
 		}
 
-		NM_CMP_FIELD (a, b, sport_range.start);
-		NM_CMP_FIELD (a, b, sport_range.end);
-		NM_CMP_FIELD (a, b, dport_range.start);
-		NM_CMP_FIELD (a, b, dport_range.end);
 		NM_CMP_FIELD_STR (a, b, iifname);
 		NM_CMP_FIELD_STR (a, b, oifname);
 		return 0;
diff --git a/src/platform/nm-platform.h b/src/platform/nm-platform.h
index fa8200e68b..97be88324e 100644
--- a/src/platform/nm-platform.h
+++ b/src/platform/nm-platform.h
@@ -819,12 +819,6 @@ typedef enum {
 } NMPlatformLinkDuplexType;
 
 typedef enum {
-	NM_PLATFORM_KERNEL_SUPPORT_EXTENDED_IFA_FLAGS                 = (1LL <<  0),
-	NM_PLATFORM_KERNEL_SUPPORT_USER_IPV6LL                        = (1LL <<  1),
-	NM_PLATFORM_KERNEL_SUPPORT_RTA_PREF                           = (1LL <<  2),
-} NMPlatformKernelSupportFlags;
-
-typedef enum {
 	NM_PLATFORM_WIREGUARD_CHANGE_FLAG_NONE                        = 0,
 	NM_PLATFORM_WIREGUARD_CHANGE_FLAG_REPLACE_PEERS               = (1LL << 0),
 	NM_PLATFORM_WIREGUARD_CHANGE_FLAG_HAS_PRIVATE_KEY             = (1LL << 1),
@@ -850,6 +844,51 @@ typedef enum {
 
 /*****************************************************************************/
 
+typedef enum {
+	NM_PLATFORM_KERNEL_SUPPORT_TYPE_EXTENDED_IFA_FLAGS,
+	NM_PLATFORM_KERNEL_SUPPORT_TYPE_USER_IPV6LL,
+	NM_PLATFORM_KERNEL_SUPPORT_TYPE_RTA_PREF,
+	NM_PLATFORM_KERNEL_SUPPORT_TYPE_FRA_L3MDEV,
+	NM_PLATFORM_KERNEL_SUPPORT_TYPE_FRA_UID_RANGE,
+	NM_PLATFORM_KERNEL_SUPPORT_TYPE_FRA_PROTOCOL,
+
+	/* this also includes FRA_SPORT_RANGE and FRA_DPORT_RANGE which
+	 * were added at the same time. */
+	NM_PLATFORM_KERNEL_SUPPORT_TYPE_FRA_IP_PROTO,
+
+	_NM_PLATFORM_KERNEL_SUPPORT_NUM,
+} NMPlatformKernelSupportType;
+
+extern volatile int _nm_platform_kernel_support_state[_NM_PLATFORM_KERNEL_SUPPORT_NUM];
+
+int _nm_platform_kernel_support_init (NMPlatformKernelSupportType type,
+                                      int value);
+
+#define _nm_platform_kernel_support_detected(type) \
+	G_LIKELY (({ \
+		const NMPlatformKernelSupportType _type = (type); \
+		\
+		nm_assert (_NM_INT_NOT_NEGATIVE (_type) && _type < G_N_ELEMENTS (_nm_platform_kernel_support_state)); \
+		\
+		(_nm_platform_kernel_support_state[_type] != 0); \
+	}))
+
+#define nm_platform_kernel_support_get(type) \
+	({ \
+		const NMPlatformKernelSupportType _type = (type); \
+		int _v; \
+		\
+		nm_assert (_NM_INT_NOT_NEGATIVE (_type) && _type < G_N_ELEMENTS (_nm_platform_kernel_support_state)); \
+		\
+		_v = _nm_platform_kernel_support_state[_type]; \
+		if (G_UNLIKELY (_v == 0)) \
+			_v = _nm_platform_kernel_support_init (_type, 0); \
+		\
+		(_v >= 0); \
+	})
+
+/*****************************************************************************/
+
 struct _NMPlatformPrivate;
 
 struct _NMPlatform {
@@ -1054,9 +1093,6 @@ typedef struct {
 	int (*tfilter_add)   (NMPlatform *self,
 	                      NMPNlmFlags flags,
 	                      const NMPlatformTfilter *tfilter);
-
-	NMPlatformKernelSupportFlags (*check_kernel_support) (NMPlatform * self,
-	                                                      NMPlatformKernelSupportFlags request_flags);
 } NMPlatformClass;
 
 /* NMPlatform signals
@@ -1668,9 +1704,6 @@ void nm_platform_lnk_wireguard_hash_update (const NMPlatformLnkWireGuard *obj, N
 void nm_platform_qdisc_hash_update (const NMPlatformQdisc *obj, NMHashState *h);
 void nm_platform_tfilter_hash_update (const NMPlatformTfilter *obj, NMHashState *h);
 
-NMPlatformKernelSupportFlags nm_platform_check_kernel_support (NMPlatform *self,
-                                                               NMPlatformKernelSupportFlags request_flags);
-
 const char *nm_platform_link_flags2str (unsigned flags, char *buf, gsize len);
 const char *nm_platform_link_inet6_addrgenmode2str (guint8 mode, char *buf, gsize len);
 const char *nm_platform_addr_flags2str (unsigned flags, char *buf, gsize len);
diff --git a/src/platform/tests/monitor.c b/src/platform/tests/monitor.c
index f0e3e6cfd0..fff5967be9 100644
--- a/src/platform/tests/monitor.c
+++ b/src/platform/tests/monitor.c
@@ -77,8 +77,6 @@ main (int argc, char **argv)
 
 	nm_linux_platform_setup ();
 
-	nm_platform_check_kernel_support (NM_PLATFORM_GET, ~((NMPlatformKernelSupportFlags) 0));
-
 	if (global_opt.persist)
 		g_main_loop_run (loop);
 
diff --git a/src/platform/tests/test-link.c b/src/platform/tests/test-link.c
index 03999fede3..eb41813b2f 100644
--- a/src/platform/tests/test-link.c
+++ b/src/platform/tests/test-link.c
@@ -521,8 +521,7 @@ test_bridge_addr (void)
 	plink = nm_platform_link_get (NM_PLATFORM_GET, link.ifindex);
 	g_assert (plink);
 
-	if (nm_platform_check_kernel_support (NM_PLATFORM_GET,
-	                                      NM_PLATFORM_KERNEL_SUPPORT_USER_IPV6LL)) {
+	if (nm_platform_kernel_support_get (NM_PLATFORM_KERNEL_SUPPORT_TYPE_USER_IPV6LL)) {
 		g_assert (!nm_platform_link_get_user_ipv6ll_enabled (NM_PLATFORM_GET, link.ifindex));
 		g_assert_cmpint (_nm_platform_uint8_inv (plink->inet6_addr_gen_mode_inv), ==, NM_IN6_ADDR_GEN_MODE_EUI64);