kernel-interface: add an exchange initiator parameter to add_sa()

This new flag gives the kernel-interface a hint how it should priorize the
use of newly installed SAs during rekeying.

Consider the following rekey procedure in IKEv2:

Initiator  ---    Responder

I1 -------CREATE-------> R1
I2 <------CREATE--------
   -------DELETE-------> R2
I3 <------DELETE--------

SAs are always handled as pairs, the following happens at the SA level:

  * Initiator starts the exchange at I1
  * Responder installs new SA pair at R1
  * Initiator installs new SA pair at I2
  * Responder removes old SA pair at R2
  * Initiator removes old SA pair at I3

This makes sure SAs get installed/removed overlapping during rekeying. However,
to avoid any packet loss, it is crucial that the new outbound SA gets
activated at the correct position:

  * as exchange initiator, in I2
  * as exchange responder, in R2

This should guarantee that we don't use the new outbound SA before the peer
could install its corresponding inbound SA.

The new parameter allows the kernel backend to install the new SA with
appropriate priorities, i.e. it should:

  * as exchange inititator, have the new outbound SA installed with higher
    priority than the old SA
  * as exchange responder, have the new outbound SA installed with lower
    priority than the old SA

While we could split up the SA installation at the responder, this approach
has another advantage: it allows the kernel backend to switch SAs based on
other criteria, for example when receiving traffic on the new inbound SA.

14 files changed, 46 insertions, 35 deletions

diff --git a/src/charon-tkm/src/tkm/tkm_kernel_ipsec.c b/src/charon-tkm/src/tkm/tkm_kernel_ipsec.c
index a276166e2..1d070fd5f 100644
--- a/src/charon-tkm/src/tkm/tkm_kernel_ipsec.c
+++ b/src/charon-tkm/src/tkm/tkm_kernel_ipsec.c
@@ -92,7 +92,7 @@ METHOD(kernel_ipsec_t, add_sa, status_t,
 	u_int32_t spi, u_int8_t protocol, u_int32_t reqid, mark_t mark,
 	u_int32_t tfc, lifetime_cfg_t *lifetime, u_int16_t enc_alg, chunk_t enc_key,
 	u_int16_t int_alg, chunk_t int_key, ipsec_mode_t mode, u_int16_t ipcomp,
-	u_int16_t cpi, bool encap, bool esn, bool inbound,
+	u_int16_t cpi, bool _initiator, bool encap, bool esn, bool inbound,
 	traffic_selector_t* src_ts, traffic_selector_t* dst_ts)
 {
 	esa_info_t esa;
@@ -120,6 +120,7 @@ METHOD(kernel_ipsec_t, add_sa, status_t,
 	}
 
 	/* Initiator if encr_r is passed as enc_key to the inbound add_sa call */
+	/* TODO: does the new _initiator parameter have the same meaning? */
 	initiator = esa.is_encr_r && inbound;
 	if (initiator)
 	{
diff --git a/src/frontends/android/jni/libandroidbridge/kernel/android_ipsec.c b/src/frontends/android/jni/libandroidbridge/kernel/android_ipsec.c
index c37ca26ab..d58e8d537 100644
--- a/src/frontends/android/jni/libandroidbridge/kernel/android_ipsec.c
+++ b/src/frontends/android/jni/libandroidbridge/kernel/android_ipsec.c
@@ -65,7 +65,7 @@ METHOD(kernel_ipsec_t, add_sa, status_t,
 	u_int32_t spi, u_int8_t protocol, u_int32_t reqid, mark_t mark,
 	u_int32_t tfc, lifetime_cfg_t *lifetime, u_int16_t enc_alg, chunk_t enc_key,
 	u_int16_t int_alg, chunk_t int_key, ipsec_mode_t mode, u_int16_t ipcomp,
-	u_int16_t cpi, bool encap, bool esn, bool inbound,
+	u_int16_t cpi, bool initiator, bool encap, bool esn, bool inbound,
 	traffic_selector_t *src_ts, traffic_selector_t *dst_ts)
 {
 	return ipsec->sas->add_sa(ipsec->sas, src, dst, spi, protocol, reqid, mark,
diff --git a/src/libcharon/plugins/load_tester/load_tester_ipsec.c b/src/libcharon/plugins/load_tester/load_tester_ipsec.c
index 49e35c4ca..bf08d2c9c 100644
--- a/src/libcharon/plugins/load_tester/load_tester_ipsec.c
+++ b/src/libcharon/plugins/load_tester/load_tester_ipsec.c
@@ -54,7 +54,7 @@ METHOD(kernel_ipsec_t, add_sa, status_t,
 	u_int32_t spi, u_int8_t protocol, u_int32_t reqid, mark_t mark,
 	u_int32_t tfc, lifetime_cfg_t *lifetime, u_int16_t enc_alg, chunk_t enc_key,
 	u_int16_t int_alg, chunk_t int_key, ipsec_mode_t mode, u_int16_t ipcomp,
-	u_int16_t cpi, bool encap, bool esn, bool inbound,
+	u_int16_t cpi, bool initiator, bool encap, bool esn, bool inbound,
 	traffic_selector_t *src_ts, traffic_selector_t *dst_ts)
 {
 	return SUCCESS;
diff --git a/src/libcharon/sa/child_sa.c b/src/libcharon/sa/child_sa.c
index a14b03949..f50e32ff1 100644
--- a/src/libcharon/sa/child_sa.c
+++ b/src/libcharon/sa/child_sa.c
@@ -607,9 +607,9 @@ METHOD(child_sa_t, alloc_cpi, u_int16_t,
 }
 
 METHOD(child_sa_t, install, status_t,
-	   private_child_sa_t *this, chunk_t encr, chunk_t integ, u_int32_t spi,
-	   u_int16_t cpi, bool inbound, bool tfcv3, linked_list_t *my_ts,
-	   linked_list_t *other_ts)
+	private_child_sa_t *this, chunk_t encr, chunk_t integ, u_int32_t spi,
+	u_int16_t cpi, bool initiator, bool inbound, bool tfcv3,
+	linked_list_t *my_ts, linked_list_t *other_ts)
 {
 	u_int16_t enc_alg = ENCR_UNDEFINED, int_alg = AUTH_UNDEFINED, size;
 	u_int16_t esn = NO_EXT_SEQ_NUMBERS;
@@ -703,7 +703,8 @@ METHOD(child_sa_t, install, status_t,
 				src, dst, spi, proto_ike2ip(this->protocol), this->reqid,
 				inbound ? this->mark_in : this->mark_out, tfc,
 				lifetime, enc_alg, encr, int_alg, integ, this->mode,
-				this->ipcomp, cpi, this->encap, esn, update, src_ts, dst_ts);
+				this->ipcomp, cpi, initiator, this->encap, esn, update,
+				src_ts, dst_ts);
 
 	free(lifetime);
 
diff --git a/src/libcharon/sa/child_sa.h b/src/libcharon/sa/child_sa.h
index 44511edf8..aa44dbfad 100644
--- a/src/libcharon/sa/child_sa.h
+++ b/src/libcharon/sa/child_sa.h
@@ -321,6 +321,7 @@ struct child_sa_t {
 	 * @param integ		integrity key
 	 * @param spi		SPI to use, allocated for inbound
 	 * @param cpi		CPI to use, allocated for outbound
+	 * @param initiator	TRUE if initiator of exchange resulting in this SA
 	 * @param inbound	TRUE to install an inbound SA, FALSE for outbound
 	 * @param tfcv3		TRUE if peer supports ESPv3 TFC
 	 * @param my_ts		negotiated local traffic selector list
@@ -328,7 +329,8 @@ struct child_sa_t {
 	 * @return			SUCCESS or FAILED
 	 */
 	status_t (*install)(child_sa_t *this, chunk_t encr, chunk_t integ,
-						u_int32_t spi, u_int16_t cpi, bool inbound, bool tfcv3,
+						u_int32_t spi, u_int16_t cpi,
+						bool initiator, bool inbound, bool tfcv3,
 						linked_list_t *my_ts, linked_list_t *other_ts);
 	/**
 	 * Install the policies using some traffic selectors.
diff --git a/src/libcharon/sa/ikev1/tasks/quick_mode.c b/src/libcharon/sa/ikev1/tasks/quick_mode.c
index 47c844e5f..52ea34b1a 100644
--- a/src/libcharon/sa/ikev1/tasks/quick_mode.c
+++ b/src/libcharon/sa/ikev1/tasks/quick_mode.c
@@ -306,17 +306,21 @@ static bool install(private_quick_mode_t *this)
 	{
 		if (this->initiator)
 		{
-			status_i = this->child_sa->install(this->child_sa, encr_r, integ_r,
-							this->spi_i, this->cpi_i, TRUE, FALSE, tsi, tsr);
-			status_o = this->child_sa->install(this->child_sa, encr_i, integ_i,
-							this->spi_r, this->cpi_r, FALSE, FALSE, tsi, tsr);
+			status_i = this->child_sa->install(this->child_sa,
+									encr_r, integ_r, this->spi_i, this->cpi_i,
+									this->initiator, TRUE, FALSE, tsi, tsr);
+			status_o = this->child_sa->install(this->child_sa,
+									encr_i, integ_i, this->spi_r, this->cpi_r,
+									this->initiator, FALSE, FALSE, tsi, tsr);
 		}
 		else
 		{
-			status_i = this->child_sa->install(this->child_sa, encr_i, integ_i,
-							this->spi_r, this->cpi_r, TRUE, FALSE, tsr, tsi);
-			status_o = this->child_sa->install(this->child_sa, encr_r, integ_r,
-							this->spi_i, this->cpi_i, FALSE, FALSE, tsr, tsi);
+			status_i = this->child_sa->install(this->child_sa,
+									encr_i, integ_i, this->spi_r, this->cpi_r,
+									this->initiator, TRUE, FALSE, tsr, tsi);
+			status_o = this->child_sa->install(this->child_sa,
+									encr_r, integ_r, this->spi_i, this->cpi_i,
+									this->initiator, FALSE, FALSE, tsr, tsi);
 		}
 	}
 	chunk_clear(&integ_i);
diff --git a/src/libcharon/sa/ikev2/tasks/child_create.c b/src/libcharon/sa/ikev2/tasks/child_create.c
index d1116d8a1..e4d762ad7 100644
--- a/src/libcharon/sa/ikev2/tasks/child_create.c
+++ b/src/libcharon/sa/ikev2/tasks/child_create.c
@@ -526,20 +526,20 @@ static status_t select_and_install(private_child_create_t *this,
 	{
 		if (this->initiator)
 		{
-			status_i = this->child_sa->install(this->child_sa,
-							encr_r, integ_r, this->my_spi, this->my_cpi,
+			status_i = this->child_sa->install(this->child_sa, encr_r, integ_r,
+							this->my_spi, this->my_cpi, this->initiator,
 							TRUE, this->tfcv3, my_ts, other_ts);
-			status_o = this->child_sa->install(this->child_sa,
-							encr_i, integ_i, this->other_spi, this->other_cpi,
+			status_o = this->child_sa->install(this->child_sa, encr_i, integ_i,
+							this->other_spi, this->other_cpi, this->initiator,
 							FALSE, this->tfcv3, my_ts, other_ts);
 		}
 		else
 		{
-			status_i = this->child_sa->install(this->child_sa,
-							encr_i, integ_i, this->my_spi, this->my_cpi,
+			status_i = this->child_sa->install(this->child_sa, encr_i, integ_i,
+							this->my_spi, this->my_cpi, this->initiator,
 							TRUE, this->tfcv3, my_ts, other_ts);
-			status_o = this->child_sa->install(this->child_sa,
-							encr_r, integ_r, this->other_spi, this->other_cpi,
+			status_o = this->child_sa->install(this->child_sa, encr_r, integ_r,
+							this->other_spi, this->other_cpi, this->initiator,
 							FALSE, this->tfcv3, my_ts, other_ts);
 		}
 	}
diff --git a/src/libhydra/kernel/kernel_interface.c b/src/libhydra/kernel/kernel_interface.c
index d81fa33c7..be247df30 100644
--- a/src/libhydra/kernel/kernel_interface.c
+++ b/src/libhydra/kernel/kernel_interface.c
@@ -180,7 +180,7 @@ METHOD(kernel_interface_t, add_sa, status_t,
 	u_int32_t spi, u_int8_t protocol, u_int32_t reqid, mark_t mark,
 	u_int32_t tfc, lifetime_cfg_t *lifetime, u_int16_t enc_alg, chunk_t enc_key,
 	u_int16_t int_alg, chunk_t int_key,	ipsec_mode_t mode, u_int16_t ipcomp,
-	u_int16_t cpi, bool encap, bool esn, bool inbound,
+	u_int16_t cpi, bool initiator, bool encap, bool esn, bool inbound,
 	traffic_selector_t *src_ts, traffic_selector_t *dst_ts)
 {
 	if (!this->ipsec)
@@ -189,7 +189,7 @@ METHOD(kernel_interface_t, add_sa, status_t,
 	}
 	return this->ipsec->add_sa(this->ipsec, src, dst, spi, protocol, reqid,
 			mark, tfc, lifetime, enc_alg, enc_key, int_alg, int_key, mode,
-			ipcomp, cpi, encap, esn, inbound, src_ts, dst_ts);
+			ipcomp, cpi, initiator, encap, esn, inbound, src_ts, dst_ts);
 }
 
 METHOD(kernel_interface_t, update_sa, status_t,
diff --git a/src/libhydra/kernel/kernel_interface.h b/src/libhydra/kernel/kernel_interface.h
index b333cae99..ab2b38256 100644
--- a/src/libhydra/kernel/kernel_interface.h
+++ b/src/libhydra/kernel/kernel_interface.h
@@ -143,6 +143,7 @@ struct kernel_interface_t {
 	 * @param mode			mode of the SA (tunnel, transport)
 	 * @param ipcomp		IPComp transform to use
 	 * @param cpi			CPI for IPComp
+	 * @param initiator		TRUE if initiator of the exchange creating this SA
 	 * @param encap			enable UDP encapsulation for NAT traversal
 	 * @param esn			TRUE to use Extended Sequence Numbers
 	 * @param inbound		TRUE if this is an inbound SA
@@ -157,7 +158,7 @@ struct kernel_interface_t {
 						u_int16_t enc_alg, chunk_t enc_key,
 						u_int16_t int_alg, chunk_t int_key,
 						ipsec_mode_t mode, u_int16_t ipcomp, u_int16_t cpi,
-						bool encap, bool esn, bool inbound,
+						bool initiator, bool encap, bool esn, bool inbound,
 						traffic_selector_t *src_ts, traffic_selector_t *dst_ts);
 
 	/**
diff --git a/src/libhydra/kernel/kernel_ipsec.h b/src/libhydra/kernel/kernel_ipsec.h
index f61f3c3aa..413e5920f 100644
--- a/src/libhydra/kernel/kernel_ipsec.h
+++ b/src/libhydra/kernel/kernel_ipsec.h
@@ -101,6 +101,7 @@ struct kernel_ipsec_t {
 	 * @param mode			mode of the SA (tunnel, transport)
 	 * @param ipcomp		IPComp transform to use
 	 * @param cpi			CPI for IPComp
+	 * @param initiator		TRUE if initiator of the exchange creating this SA
 	 * @param encap			enable UDP encapsulation for NAT traversal
 	 * @param esn			TRUE to use Extended Sequence Numbers
 	 * @param inbound		TRUE if this is an inbound SA
@@ -115,7 +116,7 @@ struct kernel_ipsec_t {
 						u_int16_t enc_alg, chunk_t enc_key,
 						u_int16_t int_alg, chunk_t int_key,
 						ipsec_mode_t mode, u_int16_t ipcomp, u_int16_t cpi,
-						bool encap, bool esn, bool inbound,
+						bool initiator, bool encap, bool esn, bool inbound,
 						traffic_selector_t *src_ts, traffic_selector_t *dst_ts);
 
 	/**
diff --git a/src/libhydra/plugins/kernel_klips/kernel_klips_ipsec.c b/src/libhydra/plugins/kernel_klips/kernel_klips_ipsec.c
index 32bea7383..5ca5879ff 100644
--- a/src/libhydra/plugins/kernel_klips/kernel_klips_ipsec.c
+++ b/src/libhydra/plugins/kernel_klips/kernel_klips_ipsec.c
@@ -1682,8 +1682,8 @@ METHOD(kernel_ipsec_t, add_sa, status_t,
 	u_int8_t protocol, u_int32_t reqid, mark_t mark, u_int32_t tfc,
 	lifetime_cfg_t *lifetime, u_int16_t enc_alg, chunk_t enc_key,
 	u_int16_t int_alg, chunk_t int_key, ipsec_mode_t mode,
-	u_int16_t ipcomp, u_int16_t cpi, bool encap, bool esn, bool inbound,
-	traffic_selector_t *src_ts, traffic_selector_t *dst_ts)
+	u_int16_t ipcomp, u_int16_t cpi, bool initiator, bool encap, bool esn,
+	bool inbound, traffic_selector_t *src_ts, traffic_selector_t *dst_ts)
 {
 	unsigned char request[PFKEY_BUFFER_SIZE];
 	struct sadb_msg *msg, *out;
diff --git a/src/libhydra/plugins/kernel_netlink/kernel_netlink_ipsec.c b/src/libhydra/plugins/kernel_netlink/kernel_netlink_ipsec.c
index bfb8fa889..a20804507 100644
--- a/src/libhydra/plugins/kernel_netlink/kernel_netlink_ipsec.c
+++ b/src/libhydra/plugins/kernel_netlink/kernel_netlink_ipsec.c
@@ -1170,7 +1170,7 @@ METHOD(kernel_ipsec_t, add_sa, status_t,
 	u_int32_t spi, u_int8_t protocol, u_int32_t reqid, mark_t mark,
 	u_int32_t tfc, lifetime_cfg_t *lifetime, u_int16_t enc_alg, chunk_t enc_key,
 	u_int16_t int_alg, chunk_t int_key, ipsec_mode_t mode, u_int16_t ipcomp,
-	u_int16_t cpi, bool encap, bool esn, bool inbound,
+	u_int16_t cpi, bool initiator, bool encap, bool esn, bool inbound,
 	traffic_selector_t* src_ts, traffic_selector_t* dst_ts)
 {
 	netlink_buf_t request;
@@ -1187,7 +1187,8 @@ METHOD(kernel_ipsec_t, add_sa, status_t,
 		lifetime_cfg_t lft = {{0,0,0},{0,0,0},{0,0,0}};
 		add_sa(this, src, dst, htonl(ntohs(cpi)), IPPROTO_COMP, reqid, mark,
 			   tfc, &lft, ENCR_UNDEFINED, chunk_empty, AUTH_UNDEFINED,
-			   chunk_empty, mode, ipcomp, 0, FALSE, FALSE, inbound, NULL, NULL);
+			   chunk_empty, mode, ipcomp, 0, initiator, FALSE, FALSE, inbound,
+			   NULL, NULL);
 		ipcomp = IPCOMP_NONE;
 		/* use transport mode ESP SA, IPComp uses tunnel mode */
 		mode = MODE_TRANSPORT;
diff --git a/src/libhydra/plugins/kernel_pfkey/kernel_pfkey_ipsec.c b/src/libhydra/plugins/kernel_pfkey/kernel_pfkey_ipsec.c
index ecab2827a..f00210b85 100644
--- a/src/libhydra/plugins/kernel_pfkey/kernel_pfkey_ipsec.c
+++ b/src/libhydra/plugins/kernel_pfkey/kernel_pfkey_ipsec.c
@@ -1523,8 +1523,8 @@ METHOD(kernel_ipsec_t, add_sa, status_t,
 	u_int8_t protocol, u_int32_t reqid, mark_t mark, u_int32_t tfc,
 	lifetime_cfg_t *lifetime, u_int16_t enc_alg, chunk_t enc_key,
 	u_int16_t int_alg, chunk_t int_key, ipsec_mode_t mode,
-	u_int16_t ipcomp, u_int16_t cpi, bool encap, bool esn, bool inbound,
-	traffic_selector_t *src_ts, traffic_selector_t *dst_ts)
+	u_int16_t ipcomp, u_int16_t cpi, bool initiator, bool encap, bool esn,
+	bool inbound, traffic_selector_t *src_ts, traffic_selector_t *dst_ts)
 {
 	unsigned char request[PFKEY_BUFFER_SIZE];
 	struct sadb_msg *msg, *out;
diff --git a/src/libipsec/ipsec_sa_mgr.c b/src/libipsec/ipsec_sa_mgr.c
index 28748971d..1f5d5a3b3 100644
--- a/src/libipsec/ipsec_sa_mgr.c
+++ b/src/libipsec/ipsec_sa_mgr.c
@@ -438,7 +438,7 @@ METHOD(ipsec_sa_mgr_t, add_sa, status_t,
 	u_int8_t protocol, u_int32_t reqid,	mark_t mark, u_int32_t tfc,
 	lifetime_cfg_t *lifetime, u_int16_t enc_alg, chunk_t enc_key,
 	u_int16_t int_alg, chunk_t int_key, ipsec_mode_t mode, u_int16_t ipcomp,
-	u_int16_t cpi, bool encap, bool esn, bool inbound,
+	u_int16_t cpi, bool initiator, bool encap, bool esn, bool inbound,
 	traffic_selector_t *src_ts, traffic_selector_t *dst_ts)
 {
 	ipsec_sa_entry_t *entry;