Merge branch 'kernel-netlink-sa-lastused'

Adds support for a change in Linux kernel 6.2 that allows retrieving
the last use time of an SA from the SA itself instead of having to query
the policies.

src/frontends/android/app/src/main/jni/libandroidbridge/kernel/android_ipsec.c

@@ -46,6 +46,13 @@ static void expire(uint8_t protocol, uint32_t spi, host_t *dst, bool hard)
 	charon->kernel->expire(charon->kernel, protocol, spi, dst, hard);
 }
 
+METHOD(kernel_ipsec_t, get_features, kernel_feature_t,
+	private_kernel_android_ipsec_t *this)
+{
+	return KERNEL_REQUIRE_UDP_ENCAPSULATION | KERNEL_ESP_V3_TFC |
+		   KERNEL_SA_USE_TIME;
+}
+
 METHOD(kernel_ipsec_t, get_spi, status_t,
 	private_kernel_android_ipsec_t *this, host_t *src, host_t *dst,
 	uint8_t protocol, uint32_t *spi)
@@ -166,6 +173,7 @@ kernel_android_ipsec_t *kernel_android_ipsec_create()
 	INIT(this,
 		.public = {
 			.interface = {
+				.get_features = _get_features,
 				.get_spi = _get_spi,
 				.get_cpi = _get_cpi,
 				.add_sa  = _add_sa,

src/include/linux/xfrm.h

@@ -288,7 +288,7 @@ enum xfrm_attr_type_t {
 	XFRMA_ETIMER_THRESH,
 	XFRMA_SRCADDR,		/* xfrm_address_t */
 	XFRMA_COADDR,		/* xfrm_address_t */
-	XFRMA_LASTUSED,		/* unsigned long  */
+	XFRMA_LASTUSED,		/* __u64  */
 	XFRMA_POLICY_TYPE,	/* struct xfrm_userpolicy_type */
 	XFRMA_MIGRATE,
 	XFRMA_ALG_AEAD,		/* struct xfrm_algo_aead */

src/libcharon/kernel/kernel_interface.h

@@ -79,6 +79,8 @@ enum kernel_feature_t {
 	KERNEL_NO_POLICY_UPDATES = (1<<3),
 	/** IPsec backend supports installing SPIs on policies */
 	KERNEL_POLICY_SPI = (1<<4),
+	/** IPsec backend reports use time per SA via query_sa() */
+	KERNEL_SA_USE_TIME = (1<<5),
 };
 
 /**
@@ -202,7 +204,11 @@ struct kernel_interface_t {
 						  kernel_ipsec_update_sa_t *data);
 
 	/**
-	 * Query the number of bytes processed by an SA from the SAD.
+	 * Query the number of bytes and packets processed by an SA from the SAD.
+	 *
+	 * Some implementations may also return the last use time (as indicated by
+	 * get_features()). This is a monotonic timestamp as returned by
+	 * time_monotonic().
 	 *
 	 * @param id			data identifying this SA
 	 * @param data			data to query the SA
@@ -247,11 +253,12 @@ struct kernel_interface_t {
 	 * Query the use time of a policy.
 	 *
 	 * The use time of a policy is the time the policy was used
-	 * for the last time.
+	 * for the last time. This is a monotonic timestamp as returned by
+	 * time_monotonic().
 	 *
 	 * @param id			data identifying this policy
 	 * @param data			data to query the policy
-	 * @param[out] use_time	the monotonic timestamp of this SA's last use
+	 * @param[out] use_time	the monotonic timestamp of this policy's last use
 	 * @return				SUCCESS if operation completed
 	 */
 	status_t (*query_policy)(kernel_interface_t *this,

src/libcharon/kernel/kernel_ipsec.h

@@ -269,7 +269,11 @@ struct kernel_ipsec_t {
 						  kernel_ipsec_update_sa_t *data);
 
 	/**
-	 * Query the number of bytes processed by an SA from the SAD.
+	 * Query the number of bytes and packets processed by an SA from the SAD.
+	 *
+	 * Some implementations may also return the last use time (as indicated by
+	 * get_features()). This is a monotonic timestamp as returned by
+	 * time_monotonic().
 	 *
 	 * @param id			data identifying this SA
 	 * @param data			data to query the SA
@@ -314,12 +318,11 @@ struct kernel_ipsec_t {
 	 * Query the use time of a policy.
 	 *
 	 * The use time of a policy is the time the policy was used for the last
-	 * time. It is not the system time, but a monotonic timestamp as returned
-	 * by time_monotonic.
+	 * time. This is a monotonic timestamp as returned by time_monotonic().
 	 *
 	 * @param id			data identifying this policy
 	 * @param data			data to query the policy
-	 * @param[out] use_time	the monotonic timestamp of this SA's last use
+	 * @param[out] use_time	the monotonic timestamp of this policy's last use
 	 * @return				SUCCESS if operation completed
 	 */
 	status_t (*query_policy)(kernel_ipsec_t *this,

src/libcharon/plugins/kernel_libipsec/kernel_libipsec_ipsec.c

@@ -231,7 +231,8 @@ static void expire(uint8_t protocol, uint32_t spi, host_t *dst, bool hard)
 METHOD(kernel_ipsec_t, get_features, kernel_feature_t,
 	private_kernel_libipsec_ipsec_t *this)
 {
-	return KERNEL_REQUIRE_UDP_ENCAPSULATION | KERNEL_ESP_V3_TFC;
+	return KERNEL_REQUIRE_UDP_ENCAPSULATION | KERNEL_ESP_V3_TFC |
+		   KERNEL_SA_USE_TIME;
 }
 
 METHOD(kernel_ipsec_t, get_spi, status_t,

src/libcharon/plugins/kernel_netlink/kernel_netlink_ipsec.c

@@ -44,6 +44,7 @@
 #include <sys/types.h>
 #include <sys/socket.h>
 #include <sys/ioctl.h>
+#include <sys/utsname.h>
 #include <stdint.h>
 #include <linux/ipsec.h>
 #include <linux/netlink.h>
@@ -341,6 +342,11 @@ struct private_kernel_netlink_ipsec_t {
 	 */
 	netlink_event_socket_t *socket_xfrm_events;
 
+	/**
+	 * Whether the kernel reports the last use time on SAs
+	 */
+	bool sa_lastused;
+
 	/**
 	 * Whether to install routes along policies
 	 */
@@ -1157,7 +1163,8 @@ CALLBACK(receive_events, void,
 METHOD(kernel_ipsec_t, get_features, kernel_feature_t,
 	private_kernel_netlink_ipsec_t *this)
 {
-	return KERNEL_ESP_V3_TFC | KERNEL_POLICY_SPI;
+	return KERNEL_ESP_V3_TFC | KERNEL_POLICY_SPI |
+			(this->sa_lastused ? KERNEL_SA_USE_TIME : 0);
 }
 
 /**
@@ -2210,10 +2217,33 @@ static void get_replay_state(private_kernel_netlink_ipsec_t *this,
 	free(out);
 }
 
+/**
+ * Get the last used time of an SA if provided by the kernel
+ */
+static bool get_lastused(struct nlmsghdr *hdr, uint64_t *lastused)
+{
+	struct rtattr *rta;
+	size_t rtasize;
+
+	rta = XFRM_RTA(hdr, struct xfrm_usersa_info);
+	rtasize = XFRM_PAYLOAD(hdr, struct xfrm_usersa_info);
+	while (RTA_OK(rta, rtasize))
+	{
+		if (rta->rta_type == XFRMA_LASTUSED &&
+			RTA_PAYLOAD(rta) == sizeof(*lastused))
+		{
+			*lastused = *(uint64_t*)RTA_DATA(rta);
+			return TRUE;
+		}
+		rta = RTA_NEXT(rta, rtasize);
+	}
+	return FALSE;
+}
+
 METHOD(kernel_ipsec_t, query_sa, status_t,
 	private_kernel_netlink_ipsec_t *this, kernel_ipsec_sa_id_t *id,
 	kernel_ipsec_query_sa_t *data, uint64_t *bytes, uint64_t *packets,
-	time_t *time)
+	time_t *use_time)
 {
 	netlink_buf_t request;
 	struct nlmsghdr *out = NULL, *hdr;
@@ -2291,11 +2321,20 @@ METHOD(kernel_ipsec_t, query_sa, status_t,
 		{
 			*packets = sa->curlft.packets;
 		}
-		if (time)
-		{	/* curlft contains an "use" time, but that contains a timestamp
-			 * of the first use, not the last. Last use time must be queried
-			 * on the policy on Linux */
-			*time = 0;
+		if (use_time)
+		{
+			uint64_t lastused = 0;
+
+			/* curlft.use_time contains the timestamp of the SA's first use, not
+			 * the last, but we might get the last use time in an attribute */
+			if (this->sa_lastused && get_lastused(hdr, &lastused))
+			{
+				*use_time = time_monotonic(NULL) - (time(NULL) - lastused);
+			}
+			else
+			{
+				*use_time = 0;
+			}
 		}
 		status = SUCCESS;
 	}
@@ -4037,6 +4076,30 @@ static void setup_spd_hash_thresh(private_kernel_netlink_ipsec_t *this,
 	}
 }
 
+/**
+ * Check for kernel features (currently only via version number)
+ */
+static void check_kernel_features(private_kernel_netlink_ipsec_t *this)
+{
+	struct utsname utsname;
+	int a, b, c;
+
+	if (uname(&utsname) == 0)
+	{
+		switch(sscanf(utsname.release, "%d.%d.%d", &a, &b, &c))
+		{
+			case 2:
+			case 3:
+				/* before 6.2 the kernel only provided the last used time for
+				 * specific outbound IPv6 SAs */
+				this->sa_lastused = a > 6 || (a == 6 && b >= 2);
+				break;
+			default:
+				break;
+		}
+	}
+}
+
 /*
  * Described in header.
  */
@@ -4084,6 +4147,8 @@ kernel_netlink_ipsec_t *kernel_netlink_ipsec_create()
 						"%s.plugins.kernel-netlink.port_bypass", FALSE, lib->ns),
 	);
 
+	check_kernel_features(this);
+
 	this->socket_xfrm = netlink_socket_create(NETLINK_XFRM, xfrm_msg_names,
 				lib->settings->get_bool(lib->settings,
 					"%s.plugins.kernel-netlink.parallel_xfrm", FALSE, lib->ns));

src/libcharon/plugins/kernel_netlink/kernel_netlink_shared.c

@@ -359,7 +359,7 @@ static status_t send_once(private_netlink_socket_t *this, struct nlmsghdr *in,
 
 	if (this->names)
 	{
-		DBG3(DBG_KNL, "sending %N %u: %b", this->names, in->nlmsg_type,
+		DBG4(DBG_KNL, "sending %N %u: %b", this->names, in->nlmsg_type,
 			 (u_int)seq, in, in->nlmsg_len);
 	}
 
@@ -426,7 +426,7 @@ static status_t send_once(private_netlink_socket_t *this, struct nlmsghdr *in,
 	{
 		if (this->names)
 		{
-			DBG3(DBG_KNL, "received %N %u: %b", this->names, hdr->nlmsg_type,
+			DBG4(DBG_KNL, "received %N %u: %b", this->names, hdr->nlmsg_type,
 				 hdr->nlmsg_seq, hdr, hdr->nlmsg_len);
 		}
 		memcpy(ptr, hdr, hdr->nlmsg_len);

src/libcharon/plugins/kernel_pfkey/kernel_pfkey_ipsec.c

@@ -1659,6 +1659,16 @@ static status_t get_spi_internal(private_kernel_pfkey_ipsec_t *this,
 	return SUCCESS;
 }
 
+METHOD(kernel_ipsec_t, get_features, kernel_feature_t,
+	private_kernel_pfkey_ipsec_t *this)
+{
+#ifdef __APPLE__
+	return KERNEL_SA_USE_TIME;
+#else
+	return 0;
+#endif
+}
+
 METHOD(kernel_ipsec_t, get_spi, status_t,
 	private_kernel_pfkey_ipsec_t *this, host_t *src, host_t *dst,
 	uint8_t protocol, uint32_t *spi)
@@ -2198,9 +2208,9 @@ METHOD(kernel_ipsec_t, query_sa, status_t,
 		/* OS X uses the "last" time of use in usetime */
 		*time = response.lft_current->sadb_lifetime_usetime;
 #else /* !__APPLE__ */
-		/* on Linux, sadb_lifetime_usetime is set to the "first" time of use,
-		 * which is actually correct according to PF_KEY. We have to query
-		 * policies for the last usetime. */
+		/* on Linux and FreeBSD, sadb_lifetime_usetime is set to the "first"
+		 * time of use, which is actually correct according to PF_KEY. We have
+		 * to query policies for the last usetime. */
 		*time = 0;
 #endif /* !__APPLE__ */
 	}
@@ -3308,6 +3318,7 @@ kernel_pfkey_ipsec_t *kernel_pfkey_ipsec_create()
 	INIT(this,
 		.public = {
 			.interface = {
+				.get_features = _get_features,
 				.get_spi = _get_spi,
 				.get_cpi = _get_cpi,
 				.add_sa  = _add_sa,

src/libcharon/sa/child_sa.c

@@ -759,19 +759,19 @@ METHOD(child_sa_t, get_usestats, void,
 	private_child_sa_t *this, bool inbound,
 	time_t *time, uint64_t *bytes, uint64_t *packets)
 {
-	if ((!bytes && !packets) || update_usebytes(this, inbound) != FAILED)
+	status_t status = NOT_SUPPORTED;
+	bool sa_use_time;
+
+	sa_use_time = charon->kernel->get_features(charon->kernel) & KERNEL_SA_USE_TIME;
+
+	if (bytes || packets || sa_use_time)
 	{
-		/* there was traffic since last update or the kernel interface
-		 * does not support querying the number of usebytes.
-		 */
-		if (time)
-		{
-			if (!update_usetime(this, inbound) && !bytes && !packets)
-			{
-				/* if policy query did not yield a usetime, query SAs instead */
-				update_usebytes(this, inbound);
-			}
-		}
+		status = update_usebytes(this, inbound);
+	}
+	if (time && !sa_use_time && status != FAILED)
+	{	/* query policies only if last use time is not available from SAs and
+		 * there was either traffic or querying the SA wasn't supported */
+		update_usetime(this, inbound);
 	}
 	if (time)
 	{