ikev2: accept rekey request for IKE SA

RFC 7296 describes the way to rekey IKE SAs: to rekey an IKE SA,
establish a new equivalent IKE SA with the peer to whom the old
IKE SA is shared using a CREATE_CHILD_SA within the existing IKE
SA.  An IKE SA so created inherits all of the original IKE SA's
Child SAs, and the new IKE SA is used for all control messages
needed to maintain those Child SAs.

Type: improvement
Signed-off-by: Atzm Watanabe <atzmism@gmail.com>
Change-Id: Icdf43b67c38bf183913a28a08a85236ba16343af

4 files changed, 417 insertions, 48 deletions

diff --git a/src/plugins/ikev2/ikev2.c b/src/plugins/ikev2/ikev2.c
index ad36068c34d..4ee2f60b085 100644
--- a/src/plugins/ikev2/ikev2.c
+++ b/src/plugins/ikev2/ikev2.c
@@ -211,6 +211,8 @@ ikev2_select_proposal (ikev2_sa_proposal_t * proposals,
 	rv->proposal_num = proposal->proposal_num;
 	rv->protocol_id = proposal->protocol_id;
 	RAND_bytes ((u8 *) & rv->spi, sizeof (rv->spi));
+	if (rv->protocol_id != IKEV2_PROTOCOL_IKE)
+	  rv->spi &= 0xffffffff;
 	goto done;
       }
     else
@@ -480,11 +482,10 @@ ikev2_complete_sa_data (ikev2_sa_t * sa, ikev2_sa_t * sai)
 }
 
 static void
-ikev2_calc_keys (ikev2_sa_t * sa)
+ikev2_calc_keys_internal (ikev2_sa_t *sa, u8 *skeyseed)
 {
   u8 *tmp;
   /* calculate SKEYSEED = prf(Ni | Nr, g^ir) */
-  u8 *skeyseed = 0;
   u8 *s = 0;
   u16 integ_key_len = 0, salt_len = 0;
   ikev2_sa_transform_t *tr_encr, *tr_prf, *tr_integ;
@@ -502,7 +503,6 @@ ikev2_calc_keys (ikev2_sa_t * sa)
 
   vec_append (s, sa->i_nonce);
   vec_append (s, sa->r_nonce);
-  skeyseed = ikev2_calc_prf (tr_prf, s, sa->dh_shared_key);
 
   /* Calculate S = Ni | Nr | SPIi | SPIr */
   u64 *spi;
@@ -520,7 +520,6 @@ ikev2_calc_keys (ikev2_sa_t * sa)
     salt_len * 2;
 
   keymat = ikev2_calc_prfplus (tr_prf, skeyseed, s, len);
-  vec_free (skeyseed);
   vec_free (s);
 
   int pos = 0;
@@ -568,6 +567,41 @@ ikev2_calc_keys (ikev2_sa_t * sa)
 }
 
 static void
+ikev2_calc_keys_rekey (ikev2_sa_t *sa_new, ikev2_sa_t *sa_old)
+{
+  u8 *s = 0, *skeyseed = 0;
+  ikev2_sa_transform_t *tr_prf =
+    ikev2_sa_get_td_for_type (sa_old->r_proposals, IKEV2_TRANSFORM_TYPE_PRF);
+
+  vec_append (s, sa_new->dh_shared_key);
+  vec_append (s, sa_new->i_nonce);
+  vec_append (s, sa_new->r_nonce);
+  skeyseed = ikev2_calc_prf (tr_prf, sa_old->sk_d, s);
+
+  ikev2_calc_keys_internal (sa_new, skeyseed);
+
+  vec_free (skeyseed);
+  vec_free (s);
+}
+
+static void
+ikev2_calc_keys (ikev2_sa_t *sa)
+{
+  u8 *s = 0, *skeyseed = 0;
+  ikev2_sa_transform_t *tr_prf =
+    ikev2_sa_get_td_for_type (sa->r_proposals, IKEV2_TRANSFORM_TYPE_PRF);
+
+  vec_append (s, sa->i_nonce);
+  vec_append (s, sa->r_nonce);
+  skeyseed = ikev2_calc_prf (tr_prf, s, sa->dh_shared_key);
+
+  ikev2_calc_keys_internal (sa, skeyseed);
+
+  vec_free (skeyseed);
+  vec_free (s);
+}
+
+static void
 ikev2_calc_child_keys (ikev2_sa_t *sa, ikev2_child_sa_t *child, u8 kex)
 {
   u8 *s = 0;
@@ -1410,6 +1444,110 @@ ikev2_process_create_child_sa_rekey (ikev2_sa_t *sa, ikev2_sa_t *sar,
   return 1;
 }
 
+static void
+ikev2_complete_sa_rekey (ikev2_sa_t *sa_new, ikev2_sa_t *sa_old,
+			 ikev2_sa_rekey_t *sa_rekey)
+{
+  sa_new->del = 0;
+  sa_new->rekey = 0;
+  sa_new->new_child = 0;
+  sa_new->sa_rekey = 0;
+  sa_new->last_sa_init_req_packet_data = 0;
+  sa_new->last_sa_init_res_packet_data = 0;
+  sa_new->last_msg_id = ~0;
+  sa_new->last_res_packet_data = 0;
+  sa_new->last_init_msg_id = 0;
+  clib_memset (&sa_new->stats, 0, sizeof (sa_new->stats));
+
+  sa_new->ispi = sa_rekey->ispi;
+  sa_new->rspi = sa_rekey->rspi;
+  sa_new->i_nonce = sa_rekey->i_nonce;
+  sa_new->r_nonce = sa_rekey->r_nonce;
+  sa_new->dh_group = sa_rekey->dh_group;
+  sa_new->dh_shared_key = sa_rekey->dh_shared_key;
+  sa_new->dh_private_key = sa_rekey->dh_private_key;
+  sa_new->i_dh_data = sa_rekey->i_dh_data;
+  sa_new->r_dh_data = sa_rekey->r_dh_data;
+  sa_new->i_proposals = sa_rekey->i_proposals;
+  sa_new->r_proposals = sa_rekey->r_proposals;
+
+  sa_new->sk_d = 0;
+  sa_new->sk_ai = 0;
+  sa_new->sk_ar = 0;
+  sa_new->sk_ei = 0;
+  sa_new->sk_er = 0;
+  sa_new->sk_pi = 0;
+  sa_new->sk_pr = 0;
+  ikev2_calc_keys_rekey (sa_new, sa_old);
+
+  sa_new->i_auth.data = vec_dup (sa_old->i_auth.data);
+  sa_new->i_auth.key = sa_old->i_auth.key;
+  if (sa_new->i_auth.key)
+    EVP_PKEY_up_ref (sa_new->i_auth.key);
+
+  sa_new->r_auth.data = vec_dup (sa_old->r_auth.data);
+  sa_new->r_auth.key = sa_old->r_auth.key;
+  if (sa_new->r_auth.key)
+    EVP_PKEY_up_ref (sa_new->r_auth.key);
+
+  sa_new->i_id.data = vec_dup (sa_old->i_id.data);
+  sa_new->r_id.data = vec_dup (sa_old->r_id.data);
+
+  sa_old->is_tun_itf_set = 0;
+  sa_old->tun_itf = ~0;
+  sa_old->old_id_expiration = 0;
+  sa_old->current_remote_id_mask = 0;
+  sa_old->old_remote_id = 0;
+  sa_old->old_remote_id_present = 0;
+  sa_old->childs = 0;
+  sa_old->sw_if_index = ~0;
+}
+
+static void
+ikev2_process_sa_rekey (ikev2_sa_t *sa_new, ikev2_sa_t *sa_old,
+			ikev2_sa_rekey_t *sa_rekey)
+{
+  ikev2_sa_transform_t *tr;
+
+  if (ikev2_generate_sa_init_data (sa_new) != IKEV2_GENERATE_SA_INIT_OK)
+    {
+      sa_rekey->notify_type = IKEV2_NOTIFY_MSG_INVALID_KE_PAYLOAD;
+      return;
+    }
+
+  sa_new->r_proposals =
+    ikev2_select_proposal (sa_new->i_proposals, IKEV2_PROTOCOL_IKE);
+
+  tr = ikev2_sa_get_td_for_type (sa_new->r_proposals, IKEV2_TRANSFORM_TYPE_DH);
+  if (!tr || tr->dh_type != sa_new->dh_group)
+    {
+      sa_rekey->notify_type = IKEV2_NOTIFY_MSG_INVALID_KE_PAYLOAD;
+      return;
+    }
+
+  sa_rekey->notify_type = 0;
+  sa_rekey->ispi = sa_new->i_proposals[0].spi;
+  sa_rekey->rspi = sa_new->r_proposals[0].spi;
+  sa_rekey->i_nonce = sa_new->i_nonce;
+  sa_rekey->r_nonce = sa_new->r_nonce;
+  sa_rekey->dh_group = sa_new->dh_group;
+  sa_rekey->dh_shared_key = sa_new->dh_shared_key;
+  sa_rekey->dh_private_key = sa_new->dh_private_key;
+  sa_rekey->i_dh_data = sa_new->i_dh_data;
+  sa_rekey->r_dh_data = sa_new->r_dh_data;
+  sa_rekey->i_proposals = sa_new->i_proposals;
+  sa_rekey->r_proposals = sa_new->r_proposals;
+
+  sa_new->i_nonce = 0;
+  sa_new->r_nonce = 0;
+  sa_new->dh_shared_key = 0;
+  sa_new->dh_private_key = 0;
+  sa_new->i_dh_data = 0;
+  sa_new->r_dh_data = 0;
+  sa_new->i_proposals = 0;
+  sa_new->r_proposals = 0;
+}
+
 static int
 ikev2_process_create_child_sa_req (vlib_main_t * vm,
 				   ikev2_sa_t * sa, ike_header_t * ike,
@@ -1515,7 +1653,9 @@ ikev2_process_create_child_sa_req (vlib_main_t * vm,
       p += plen;
     }
 
-  if (!proposal || proposal->protocol_id != IKEV2_PROTOCOL_ESP || !nonce)
+  if (!proposal || !nonce ||
+      (proposal->protocol_id != IKEV2_PROTOCOL_ESP &&
+       proposal->protocol_id != IKEV2_PROTOCOL_IKE))
     goto cleanup_and_exit;
 
   if (sa->is_initiator)
@@ -1571,6 +1711,16 @@ ikev2_process_create_child_sa_req (vlib_main_t * vm,
 	      vec_free (tsi);
 	    }
 	}
+      else if (proposal[0].protocol_id == IKEV2_PROTOCOL_IKE)
+	{
+	  ikev2_sa_rekey_t *sa_rekey;
+	  if (tsi || tsr)
+	    goto cleanup_and_exit;
+	  sar.i_proposals = proposal;
+	  vec_add (sar.i_nonce, nonce, nonce_len);
+	  vec_add2 (sa->sa_rekey, sa_rekey, 1);
+	  ikev2_process_sa_rekey (&sar, sa, sa_rekey);
+	}
       else
 	{
 	  /* create new child SA */
@@ -2414,19 +2564,26 @@ ikev2_add_invalid_ke_payload (ikev2_sa_t *sa, ikev2_payload_chain_t *chain)
 }
 
 static void
+ikev2_add_notify_payload (ikev2_sa_t *sa, ikev2_payload_chain_t *chain,
+			  u16 notify_type)
+{
+  if (notify_type == IKEV2_NOTIFY_MSG_INVALID_KE_PAYLOAD)
+    ikev2_add_invalid_ke_payload (sa, chain);
+  else
+    ikev2_payload_add_notify (chain, notify_type, 0);
+}
+
+static void
 ikev2_add_create_child_resp (ikev2_sa_t *sa, ikev2_rekey_t *rekey,
 			     ikev2_payload_chain_t *chain)
 {
   if (rekey->notify_type)
     {
-      if (rekey->notify_type == IKEV2_NOTIFY_MSG_INVALID_KE_PAYLOAD)
-	ikev2_add_invalid_ke_payload (sa, chain);
-      else
-	ikev2_payload_add_notify (chain, rekey->notify_type, 0);
+      ikev2_add_notify_payload (sa, chain, rekey->notify_type);
       return;
     }
 
-  ikev2_payload_add_sa (chain, rekey->r_proposal);
+  ikev2_payload_add_sa (chain, rekey->r_proposal, 0);
   ikev2_payload_add_nonce (chain, sa->r_nonce);
   if (rekey->kex)
     ikev2_payload_add_ke (chain, sa->dh_group, sa->r_dh_data);
@@ -2482,7 +2639,7 @@ ikev2_generate_message (vlib_buffer_t *b, ikev2_sa_t *sa, ike_header_t *ike,
 	  ASSERT (udp);
 
 	  ike->rspi = clib_host_to_net_u64 (sa->rspi);
-	  ikev2_payload_add_sa (chain, sa->r_proposals);
+	  ikev2_payload_add_sa (chain, sa->r_proposals, 0);
 	  ikev2_payload_add_ke (chain, sa->dh_group, sa->r_dh_data);
 	  ikev2_payload_add_nonce (chain, sa->r_nonce);
 
@@ -2510,7 +2667,7 @@ ikev2_generate_message (vlib_buffer_t *b, ikev2_sa_t *sa, ike_header_t *ike,
 	{
 	  ikev2_payload_add_id (chain, &sa->r_id, IKEV2_PAYLOAD_IDR);
 	  ikev2_payload_add_auth (chain, &sa->r_auth);
-	  ikev2_payload_add_sa (chain, sa->childs[0].r_proposals);
+	  ikev2_payload_add_sa (chain, sa->childs[0].r_proposals, 0);
 	  ikev2_payload_add_ts (chain, sa->childs[0].tsi, IKEV2_PAYLOAD_TSI);
 	  ikev2_payload_add_ts (chain, sa->childs[0].tsr, IKEV2_PAYLOAD_TSR);
 	}
@@ -2555,7 +2712,7 @@ ikev2_generate_message (vlib_buffer_t *b, ikev2_sa_t *sa, ike_header_t *ike,
 	  if (sa->r_id.type != 0)
 	    ikev2_payload_add_id (chain, &sa->r_id, IKEV2_PAYLOAD_IDR);
 	  ikev2_payload_add_auth (chain, &sa->i_auth);
-	  ikev2_payload_add_sa (chain, sa->childs[0].i_proposals);
+	  ikev2_payload_add_sa (chain, sa->childs[0].i_proposals, 0);
 	  ikev2_payload_add_ts (chain, sa->childs[0].tsi, IKEV2_PAYLOAD_TSI);
 	  ikev2_payload_add_ts (chain, sa->childs[0].tsr, IKEV2_PAYLOAD_TSR);
 	  ikev2_payload_add_notify (chain, IKEV2_NOTIFY_MSG_INITIAL_CONTACT,
@@ -2632,7 +2789,7 @@ ikev2_generate_message (vlib_buffer_t *b, ikev2_sa_t *sa, ike_header_t *ike,
 	  notify.spi = sa->childs[0].i_proposals->spi;
 	  *(u32 *) data = clib_host_to_net_u32 (notify.spi);
 
-	  ikev2_payload_add_sa (chain, proposals);
+	  ikev2_payload_add_sa (chain, proposals, 0);
 	  ikev2_payload_add_nonce (chain, sa->i_nonce);
 	  ikev2_payload_add_ts (chain, sa->childs[0].tsi, IKEV2_PAYLOAD_TSI);
 	  ikev2_payload_add_ts (chain, sa->childs[0].tsr, IKEV2_PAYLOAD_TSR);
@@ -2651,6 +2808,19 @@ ikev2_generate_message (vlib_buffer_t *b, ikev2_sa_t *sa, ike_header_t *ike,
 	  ikev2_add_create_child_resp (sa, &sa->new_child[0], chain);
 	  vec_del1 (sa->new_child, 0);
 	}
+      else if (vec_len (sa->sa_rekey) > 0)
+	{
+	  if (sa->sa_rekey[0].notify_type)
+	    ikev2_add_notify_payload (sa, chain, sa->sa_rekey[0].notify_type);
+	  else
+	    {
+	      ikev2_payload_add_sa (chain, sa->sa_rekey[0].r_proposals, 1);
+	      ikev2_payload_add_nonce (chain, sa->sa_rekey[0].r_nonce);
+	      ikev2_payload_add_ke (chain, sa->sa_rekey[0].dh_group,
+				    sa->sa_rekey[0].r_dh_data);
+	    }
+	  vec_del1 (sa->sa_rekey, 0);
+	}
       else if (sa->unsupported_cp)
 	{
 	  u8 *data = vec_new (u8, 1);
@@ -3456,6 +3626,38 @@ ikev2_node_internal (vlib_main_t *vm, vlib_node_runtime_t *node,
 			  vm, node->node_index, IKEV2_ERROR_NO_BUFF_SPACE, 1);
 		    }
 		}
+	      else if (vec_len (sa0->sa_rekey) > 0)
+		{
+		  if (!sa0->sa_rekey[0].notify_type)
+		    {
+		      ikev2_sa_t *sar, *tmp = 0;
+		      pool_get (ptd->sas, tmp);
+		      sa0 = pool_elt_at_index (ptd->sas, p[0]);
+		      /* swap old/new SAs to keep index and inherit IPsec SA */
+		      clib_memcpy_fast (tmp, sa0, sizeof (*tmp));
+		      sar = sa0;
+		      sa0 = tmp;
+		      hash_set (ptd->sa_by_rspi, sa0->rspi, sa0 - ptd->sas);
+		      p = hash_get (ptd->sa_by_rspi, sa0->rspi);
+		      ikev2_complete_sa_rekey (sar, sa0, &sa0->sa_rekey[0]);
+		      hash_set (ptd->sa_by_rspi, sar->rspi, sar - ptd->sas);
+		    }
+		  if (ike_hdr_is_response (ike0))
+		    {
+		      vec_free (sa0->sa_rekey);
+		    }
+		  else
+		    {
+		      stats->n_rekey_req++;
+		      sa0->stats.n_rekey_req++;
+		      ike0->flags = IKEV2_HDR_FLAG_RESPONSE;
+		      slen =
+			ikev2_generate_message (b0, sa0, ike0, 0, udp0, stats);
+		      if (~0 == slen)
+			vlib_node_increment_counter (
+			  vm, node->node_index, IKEV2_ERROR_NO_BUFF_SPACE, 1);
+		    }
+		}
 	    }
 	}
       else
@@ -4526,7 +4728,7 @@ ikev2_initiate_sa_init (vlib_main_t * vm, u8 * name)
   proposals[0].protocol_id = IKEV2_PROTOCOL_IKE;
 
   /* Add and then cleanup proposal data */
-  ikev2_payload_add_sa (chain, proposals);
+  ikev2_payload_add_sa (chain, proposals, 0);
   ikev2_sa_free_proposal_vector (&proposals);
 
   sa.is_initiator = 1;
@@ -4560,6 +4762,7 @@ ikev2_initiate_sa_init (vlib_main_t * vm, u8 * name)
   sa.childs[0].i_proposals[0].protocol_id = IKEV2_PROTOCOL_ESP;
   RAND_bytes ((u8 *) & sa.childs[0].i_proposals[0].spi,
 	      sizeof (sa.childs[0].i_proposals[0].spi));
+  sa.childs[0].i_proposals[0].spi &= 0xffffffff;
 
   /* Add NAT detection notification messages (mandatory) */
   u8 *nat_detection_sha1 = ikev2_compute_nat_sha1 (
@@ -4807,6 +5010,7 @@ ikev2_rekey_child_sa_internal (vlib_main_t * vm, ikev2_sa_t * sa,
 
   /*need new ispi */
   RAND_bytes ((u8 *) & proposals[0].spi, sizeof (proposals[0].spi));
+  proposals[0].spi &= 0xffffffff;
   rekey->spi = proposals[0].spi;
   rekey->ispi = csa->i_proposals->spi;
   len = ikev2_generate_message (b0, sa, ike0, proposals, 0, 0);
diff --git a/src/plugins/ikev2/ikev2_payload.c b/src/plugins/ikev2/ikev2_payload.c
index 294864d8c43..689c502d4a3 100644
--- a/src/plugins/ikev2/ikev2_payload.c
+++ b/src/plugins/ikev2/ikev2_payload.c
@@ -167,8 +167,8 @@ ikev2_payload_add_notify_2 (ikev2_payload_chain_t * c, u16 msg_type,
 }
 
 void
-ikev2_payload_add_sa (ikev2_payload_chain_t * c,
-		      ikev2_sa_proposal_t * proposals)
+ikev2_payload_add_sa (ikev2_payload_chain_t *c, ikev2_sa_proposal_t *proposals,
+		      u8 force_spi)
 {
   ike_payload_header_t *ph;
   ike_sa_proposal_data_t *prop;
@@ -184,7 +184,13 @@ ikev2_payload_add_sa (ikev2_payload_chain_t * c,
 
   vec_foreach (p, proposals)
   {
-    int spi_size = (p->protocol_id == IKEV2_PROTOCOL_ESP) ? 4 : 0;
+    int spi_size = 0;
+
+    if (p->protocol_id == IKEV2_PROTOCOL_ESP)
+      spi_size = 4;
+    else if (force_spi && p->protocol_id == IKEV2_PROTOCOL_IKE)
+      spi_size = 8;
+
     pr_data = vec_new (u8, sizeof (ike_sa_proposal_data_t) + spi_size);
     prop = (ike_sa_proposal_data_t *) pr_data;
     prop->last_or_more = proposals - p + 1 < vec_len (proposals) ? 2 : 0;
@@ -193,8 +199,13 @@ ikev2_payload_add_sa (ikev2_payload_chain_t * c,
     prop->spi_size = spi_size;
     prop->num_transforms = vec_len (p->transforms);
 
-    if (spi_size)
+    if (spi_size == 4)
       prop->spi[0] = clib_host_to_net_u32 (p->spi);
+    else if (spi_size == 8)
+      {
+	u64 s = clib_host_to_net_u64 (p->spi);
+	clib_memcpy_fast (prop->spi, &s, sizeof (s));
+      }
 
     vec_foreach (t, p->transforms)
     {
@@ -384,8 +395,9 @@ ikev2_parse_sa_payload (ike_payload_header_t * ikep, u32 rlen)
       sap = (ike_sa_proposal_data_t *) & ikep->payload[proposal_ptr];
       int i, transform_ptr;
 
-      /* IKE proposal should not have SPI */
-      if (sap->protocol_id == IKEV2_PROTOCOL_IKE && sap->spi_size != 0)
+      /* IKE proposal should have 8 bytes or no SPI */
+      if (sap->protocol_id == IKEV2_PROTOCOL_IKE && sap->spi_size != 0 &&
+	  sap->spi_size != 8)
 	goto data_corrupted;
 
       /* IKE proposal should not have SPI */
@@ -404,6 +416,12 @@ ikev2_parse_sa_payload (ike_payload_header_t * ikep, u32 rlen)
 	{
 	  proposal->spi = clib_net_to_host_u32 (sap->spi[0]);
 	}
+      else if (sap->spi_size == 8)
+	{
+	  u64 s;
+	  clib_memcpy_fast (&s, &sap->spi[0], sizeof (s));
+	  proposal->spi = clib_net_to_host_u64 (s);
+	}
 
       for (i = 0; i < sap->num_transforms; i++)
 	{
diff --git a/src/plugins/ikev2/ikev2_priv.h b/src/plugins/ikev2/ikev2_priv.h
index dca2fe80c57..a11538f92c7 100644
--- a/src/plugins/ikev2/ikev2_priv.h
+++ b/src/plugins/ikev2/ikev2_priv.h
@@ -243,7 +243,7 @@ typedef struct
 {
   u8 proposal_num;
   ikev2_protocol_id_t protocol_id:8;
-  u32 spi;
+  u64 spi;
   ikev2_sa_transform_t *transforms;
 } ikev2_sa_proposal_t;
 
@@ -330,6 +330,22 @@ typedef struct
 
 typedef struct
 {
+  u16 notify_type;
+  u16 dh_group;
+  u64 ispi;
+  u64 rspi;
+  u8 *i_nonce;
+  u8 *r_nonce;
+  u8 *dh_shared_key;
+  u8 *dh_private_key;
+  u8 *i_dh_data;
+  u8 *r_dh_data;
+  ikev2_sa_proposal_t *i_proposals;
+  ikev2_sa_proposal_t *r_proposals;
+} ikev2_sa_rekey_t;
+
+typedef struct
+{
   u16 msg_type;
   u8 protocol_id;
   u32 spi;
@@ -432,6 +448,9 @@ typedef struct
 
   ikev2_rekey_t *new_child;
 
+  /* pending sa rekeyings */
+  ikev2_sa_rekey_t *sa_rekey;
+
   /* packet data */
   u8 *last_sa_init_req_packet_data;
   u8 *last_sa_init_res_packet_data;
@@ -601,8 +620,8 @@ void ikev2_payload_add_notify (ikev2_payload_chain_t * c, u16 msg_type,
 			       u8 * data);
 void ikev2_payload_add_notify_2 (ikev2_payload_chain_t * c, u16 msg_type,
 				 u8 * data, ikev2_notify_t * notify);
-void ikev2_payload_add_sa (ikev2_payload_chain_t * c,
-			   ikev2_sa_proposal_t * proposals);
+void ikev2_payload_add_sa (ikev2_payload_chain_t *c,
+			   ikev2_sa_proposal_t *proposals, u8 force_spi);
 void ikev2_payload_add_ke (ikev2_payload_chain_t * c, u16 dh_group,
 			   u8 * dh_data);
 void ikev2_payload_add_nonce (ikev2_payload_chain_t * c, u8 * nonce);
diff --git a/test/test_ikev2.py b/test/test_ikev2.py
index 30ee2b98110..d2b4c691f85 100644
--- a/test/test_ikev2.py
+++ b/test/test_ikev2.py
@@ -361,14 +361,21 @@ class IKEv2SA(object):
         h.update(data)
         return h.finalize()
 
-    def calc_keys(self):
+    def calc_keys(self, sk_d=None):
         prf = self.ike_prf_alg.mod()
-        # SKEYSEED = prf(Ni | Nr, g^ir)
-        s = self.i_nonce + self.r_nonce
-        self.skeyseed = self.calc_prf(prf, s, self.dh_shared_secret)
+        if sk_d is None:
+            # SKEYSEED = prf(Ni | Nr, g^ir)
+            self.skeyseed = self.calc_prf(
+                prf, self.i_nonce + self.r_nonce, self.dh_shared_secret
+            )
+        else:
+            # SKEYSEED = prf(SK_d (old), g^ir (new) | Ni | Nr)
+            self.skeyseed = self.calc_prf(
+                prf, sk_d, self.dh_shared_secret + self.i_nonce + self.r_nonce
+            )
 
         # calculate S = Ni | Nr | SPIi SPIr
-        s = s + self.ispi + self.rspi
+        s = self.i_nonce + self.r_nonce + self.ispi + self.rspi
 
         prf_key_trunc = self.ike_prf_alg.trunc_len
         encr_key_len = self.ike_crypto_key_len
@@ -585,6 +592,45 @@ class IKEv2SA(object):
         digest.update(data)
         return digest.finalize()
 
+    def clone(self, test, **kwargs):
+        if "spi" not in kwargs:
+            kwargs["spi"] = self.ispi if self.is_initiator else self.rspi
+        if "nonce" not in kwargs:
+            kwargs["nonce"] = self.i_nonce if self.is_initiator else self.r_nonce
+        if self.child_sas:
+            if "local_ts" not in kwargs:
+                kwargs["local_ts"] = self.child_sas[0].local_ts
+            if "remote_ts" not in kwargs:
+                kwargs["remote_ts"] = self.child_sas[0].remote_ts
+        sa = type(self)(
+            test,
+            is_initiator=self.is_initiator,
+            i_id=self.i_id,
+            r_id=self.r_id,
+            id_type=self.id_type,
+            auth_data=self.auth_data,
+            auth_method=self.auth_method,
+            priv_key=self.priv_key,
+            i_natt=self.i_natt,
+            r_natt=self.r_natt,
+            udp_encap=self.udp_encap,
+            **kwargs,
+        )
+        if sa.is_initiator:
+            sa.set_ike_props(
+                crypto=self.ike_crypto,
+                crypto_key_len=self.ike_crypto_key_len,
+                integ=self.ike_integ,
+                prf=self.ike_prf,
+                dh=self.ike_dh,
+            )
+            sa.set_esp_props(
+                crypto=self.esp_crypto,
+                crypto_key_len=self.esp_crypto_key_len,
+                integ=self.esp_integ,
+            )
+        return sa
+
 
 @unittest.skipIf("ikev2" in config.excluded_plugins, "Exclude IKEv2 plugin tests")
 class IkePeer(VppTestCase):
@@ -650,6 +696,20 @@ class IkePeer(VppTestCase):
             self.pg0, ike_msg, self.sa.sport, self.sa.dport, self.sa.natt, self.ip6
         )
 
+    def create_sa_rekey_request(self, **kwargs):
+        sa = self.generate_sa_init_payload(**kwargs)
+        header = ikev2.IKEv2(
+            init_SPI=self.sa.ispi,
+            resp_SPI=self.sa.rspi,
+            id=self.sa.new_msg_id(),
+            flags="Initiator",
+            exch_type="CREATE_CHILD_SA",
+        )
+        ike_msg = self.encrypt_ike_msg(header, sa, "SA")
+        return self.create_packet(
+            self.pg0, ike_msg, self.sa.sport, self.sa.dport, self.sa.natt, self.ip6
+        )
+
     def create_empty_request(self):
         header = ikev2.IKEv2(
             init_SPI=self.sa.ispi,
@@ -830,10 +890,15 @@ class IkePeer(VppTestCase):
         self.assertEqual(api_id.data_len, exp_id.data_len)
         self.assertEqual(bytes(api_id.data, "ascii"), exp_id.type)
 
-    def verify_ike_sas(self):
+    def verify_ike_sas(self, is_rekey=False):
         r = self.vapi.ikev2_sa_dump()
-        self.assertEqual(len(r), 1)
-        sa = r[0].sa
+        if is_rekey:
+            sa_count = 2
+            sa = r[1].sa
+        else:
+            sa_count = 1
+            sa = r[0].sa
+        self.assertEqual(len(r), sa_count)
         self.assertEqual(self.sa.ispi, (sa.ispi).to_bytes(8, "big"))
         self.assertEqual(self.sa.rspi, (sa.rspi).to_bytes(8, "big"))
         if self.ip6:
@@ -865,7 +930,16 @@ class IkePeer(VppTestCase):
         self.assertEqual(bytes(sa.i_id.data, "ascii"), self.sa.i_id)
         self.assertEqual(bytes(sa.r_id.data, "ascii"), self.idr)
 
+        n = self.vapi.ikev2_nonce_get(is_initiator=True, sa_index=sa.sa_index)
+        self.verify_nonce(n, self.sa.i_nonce)
+        n = self.vapi.ikev2_nonce_get(is_initiator=False, sa_index=sa.sa_index)
+        self.verify_nonce(n, self.sa.r_nonce)
+
         r = self.vapi.ikev2_child_sa_dump(sa_index=sa.sa_index)
+        if is_rekey:
+            self.assertEqual(len(r), 0)
+            return
+
         self.assertEqual(len(r), 1)
         csa = r[0].child_sa
         self.assertEqual(csa.sa_index, sa.sa_index)
@@ -894,11 +968,6 @@ class IkePeer(VppTestCase):
         self.assertEqual(len(r), 1)
         self.verify_ts(r[0].ts, tsr[0], False)
 
-        n = self.vapi.ikev2_nonce_get(is_initiator=True, sa_index=sa.sa_index)
-        self.verify_nonce(n, self.sa.i_nonce)
-        n = self.vapi.ikev2_nonce_get(is_initiator=False, sa_index=sa.sa_index)
-        self.verify_nonce(n, self.sa.r_nonce)
-
     def verify_nonce(self, api_nonce, nonce):
         self.assertEqual(api_nonce.data_len, len(nonce))
         self.assertEqual(api_nonce.nonce, nonce)
@@ -1281,7 +1350,9 @@ class TemplateResponder(IkePeer):
         capture = self.pg0.get_capture(1)
         self.verify_del_sa(capture[0])
 
-    def send_sa_init_req(self):
+    def generate_sa_init_payload(
+        self, spi=None, dh_pub_key=None, nonce=None, next_payload=None
+    ):
         tr_attr = self.sa.ike_crypto_attr()
         trans = (
             ikev2.IKEv2_payload_Transform(
@@ -1301,23 +1372,36 @@ class TemplateResponder(IkePeer):
             )
         )
 
+        if spi is None:
+            pargs = {}
+        else:
+            pargs = {"SPI": spi, "SPIsize": len(spi)}
         props = ikev2.IKEv2_payload_Proposal(
-            proposal=1, proto="IKEv2", trans_nb=4, trans=trans
+            proposal=1,
+            proto="IKEv2",
+            trans_nb=4,
+            trans=trans,
+            **pargs,
         )
 
-        next_payload = None if self.ip6 else "Notify"
-
-        self.sa.init_req_packet = (
-            ikev2.IKEv2(
-                init_SPI=self.sa.ispi, flags="Initiator", exch_type="IKE_SA_INIT"
-            )
-            / ikev2.IKEv2_payload_SA(next_payload="KE", prop=props)
+        return (
+            ikev2.IKEv2_payload_SA(next_payload="KE", prop=props)
             / ikev2.IKEv2_payload_KE(
-                next_payload="Nonce", group=self.sa.ike_dh, load=self.sa.my_dh_pub_key
+                next_payload="Nonce",
+                group=self.sa.ike_dh,
+                load=self.sa.my_dh_pub_key if dh_pub_key is None else dh_pub_key,
+            )
+            / ikev2.IKEv2_payload_Nonce(
+                next_payload=next_payload,
+                load=self.sa.i_nonce if nonce is None else nonce,
             )
-            / ikev2.IKEv2_payload_Nonce(next_payload=next_payload, load=self.sa.i_nonce)
         )
 
+    def send_sa_init_req(self):
+        self.sa.init_req_packet = ikev2.IKEv2(
+            init_SPI=self.sa.ispi, flags="Initiator", exch_type="IKE_SA_INIT"
+        ) / self.generate_sa_init_payload(next_payload=None if self.ip6 else "Notify")
+
         if not self.ip6:
             if self.sa.i_natt:
                 src_address = b"\x0a\x0a\x0a\x01"
@@ -2186,6 +2270,50 @@ class TestResponderRekeyRepeatKEX(TestResponderRekeyRepeat):
     WITH_KEX = True
 
 
+@tag_fixme_vpp_workers
+class TestResponderRekeySA(TestResponderPsk):
+    """test ikev2 responder - rekey IKE SA"""
+
+    def send_rekey_from_initiator(self, newsa):
+        packet = self.create_sa_rekey_request(
+            spi=newsa.ispi,
+            dh_pub_key=newsa.my_dh_pub_key,
+            nonce=newsa.i_nonce,
+        )
+        self.pg0.add_stream(packet)
+        self.pg0.enable_capture()
+        self.pg_start()
+        capture = self.pg0.get_capture(1)
+        return capture
+
+    def process_rekey_response(self, newsa, capture):
+        ih = self.get_ike_header(capture[0])
+        plain = self.sa.hmac_and_decrypt(ih)
+        sa = ikev2.IKEv2_payload_SA(plain)
+        prop = sa[ikev2.IKEv2_payload_Proposal]
+        newsa.rspi = prop.SPI
+        newsa.r_nonce = sa[ikev2.IKEv2_payload_Nonce].load
+        newsa.r_dh_data = sa[ikev2.IKEv2_payload_KE].load
+        newsa.complete_dh_data()
+        newsa.calc_keys(sk_d=self.sa.sk_d)
+        newsa.child_sas = self.sa.child_sas
+        self.sa.child_sas = []
+
+    def test_responder(self):
+        super(TestResponderRekeySA, self).test_responder()
+        newsa = self.sa.clone(self, spi=os.urandom(8))
+        newsa.generate_dh_data()
+        capture = self.send_rekey_from_initiator(newsa)
+        self.process_rekey_response(newsa, capture)
+        self.verify_ike_sas(is_rekey=True)
+        self.assert_counter(1, "rekey_req", "ip4")
+        r = self.vapi.ikev2_sa_dump()
+        self.assertEqual(r[1].sa.stats.n_rekey_req, 1)
+        self.initiate_del_sa_from_initiator()
+        self.sa = newsa
+        self.verify_ike_sas()
+
+
 @tag_fixme_ubuntu2204
 @tag_fixme_debian11
 class TestResponderVrf(TestResponderPsk, Ikev2Params):