ipsec: new api for sa ips and ports updates

Useful to update the tunnel paramaters and udp ports (NAT-T) of an SA
without having to rekey. Could be done by deleting and re-adding the
SA but it would not preserve the anti-replay window if there is one.
Use case: a nat update/reboot between the 2 endpoints of the tunnel.

Type: feature
Change-Id: Icf5c0aac218603e8aa9a008ed6f614e4a6db59a0
Signed-off-by: Arthur de Kerhor <arthurdekerhor@gmail.com>

5 files changed, 186 insertions, 0 deletions

diff --git a/src/vnet/ipsec/ipsec.api b/src/vnet/ipsec/ipsec.api
index 56ad646d001..6cbad6e74fa 100644
--- a/src/vnet/ipsec/ipsec.api
+++ b/src/vnet/ipsec/ipsec.api
@@ -201,6 +201,28 @@ autoreply define ipsec_sad_entry_del
   u32 id;
 };
 
+/** \brief An API to update the tunnel parameters and the ports associated with an SA
+
+    Used in the NAT-T case when the NAT data changes
+    @param client_index - opaque cookie to identify the sender
+    @param context - sender context, to match reply w/ request
+    @param sa_id - the id of the SA to update
+    @param is_tun - update the tunnel if non-zero, else update only the ports
+    @param tunnel - sender context, to match reply w/ request
+    @param udp_src_port - new src port for NAT-T. Used if different from 0xffff
+    @param udp_dst_port - new dst port for NAT-T. Used if different from 0xffff
+ */
+autoreply define ipsec_sad_entry_update
+{
+  u32 client_index;
+  u32 context;
+  u32 sad_id;
+  bool is_tun;
+  vl_api_tunnel_t tunnel;
+  u16 udp_src_port [default=0xffff];
+  u16 udp_dst_port [default=0xffff];
+};
+
 define ipsec_sad_entry_add_del_reply
 {
   option deprecated;
diff --git a/src/vnet/ipsec/ipsec_api.c b/src/vnet/ipsec/ipsec_api.c
index 378f493ec14..3994150d895 100644
--- a/src/vnet/ipsec/ipsec_api.c
+++ b/src/vnet/ipsec/ipsec_api.c
@@ -568,6 +568,31 @@ vl_api_ipsec_sad_entry_add_t_handler (vl_api_ipsec_sad_entry_add_t *mp)
 }
 
 static void
+vl_api_ipsec_sad_entry_update_t_handler (vl_api_ipsec_sad_entry_update_t *mp)
+{
+  vl_api_ipsec_sad_entry_update_reply_t *rmp;
+  u32 id;
+  tunnel_t tun = { 0 };
+  int rv;
+
+  id = ntohl (mp->sad_id);
+
+  if (mp->is_tun)
+    {
+      rv = tunnel_decode (&mp->tunnel, &tun);
+
+      if (rv)
+	goto out;
+    }
+
+  rv = ipsec_sa_update (id, htons (mp->udp_src_port), htons (mp->udp_dst_port),
+			&tun, mp->is_tun);
+
+out:
+  REPLY_MACRO (VL_API_IPSEC_SAD_ENTRY_UPDATE_REPLY);
+}
+
+static void
 send_ipsec_spds_details (ipsec_spd_t * spd, vl_api_registration_t * reg,
 			 u32 context)
 {
diff --git a/src/vnet/ipsec/ipsec_sa.c b/src/vnet/ipsec/ipsec_sa.c
index a330abcb244..295323b8f7e 100644
--- a/src/vnet/ipsec/ipsec_sa.c
+++ b/src/vnet/ipsec/ipsec_sa.c
@@ -172,6 +172,137 @@ ipsec_sa_set_async_op_ids (ipsec_sa_t * sa)
 }
 
 int
+ipsec_sa_update (u32 id, u16 src_port, u16 dst_port, const tunnel_t *tun,
+		 bool is_tun)
+{
+  ipsec_main_t *im = &ipsec_main;
+  ipsec_sa_t *sa;
+  u32 sa_index;
+  uword *p;
+  int rv;
+
+  p = hash_get (im->sa_index_by_sa_id, id);
+  if (!p)
+    return VNET_API_ERROR_NO_SUCH_ENTRY;
+
+  sa = ipsec_sa_get (p[0]);
+  sa_index = sa - ipsec_sa_pool;
+
+  if (is_tun && ipsec_sa_is_set_IS_TUNNEL (sa) &&
+      (ip_address_cmp (&tun->t_src, &sa->tunnel.t_src) != 0 ||
+       ip_address_cmp (&tun->t_dst, &sa->tunnel.t_dst) != 0))
+    {
+      /* if the source IP is updated for an inbound SA under a tunnel protect,
+       we need to update the tun_protect DB with the new src IP */
+      if (ipsec_sa_is_set_IS_INBOUND (sa) &&
+	  ip_address_cmp (&tun->t_src, &sa->tunnel.t_src) != 0 &&
+	  !ip46_address_is_zero (&tun->t_src.ip))
+	{
+	  if (ip46_address_is_ip4 (&sa->tunnel.t_src.ip))
+	    {
+	      ipsec4_tunnel_kv_t old_key, new_key;
+	      clib_bihash_kv_8_16_t res,
+		*bkey = (clib_bihash_kv_8_16_t *) &old_key;
+
+	      ipsec4_tunnel_mk_key (&old_key, &sa->tunnel.t_src.ip.ip4,
+				    clib_host_to_net_u32 (sa->spi));
+	      ipsec4_tunnel_mk_key (&new_key, &tun->t_src.ip.ip4,
+				    clib_host_to_net_u32 (sa->spi));
+
+	      if (!clib_bihash_search_8_16 (&im->tun4_protect_by_key, bkey,
+					    &res))
+		{
+		  clib_bihash_add_del_8_16 (&im->tun4_protect_by_key, &res, 0);
+		  res.key = new_key.key;
+		  clib_bihash_add_del_8_16 (&im->tun4_protect_by_key, &res, 1);
+		}
+	    }
+	  else
+	    {
+	      ipsec6_tunnel_kv_t old_key = {
+          .key = {
+            .remote_ip =  sa->tunnel.t_src.ip.ip6,
+            .spi = clib_host_to_net_u32 (sa->spi),
+          },
+        }, new_key = {
+          .key = {
+            .remote_ip = tun->t_src.ip.ip6,
+            .spi = clib_host_to_net_u32 (sa->spi),
+          }};
+	      clib_bihash_kv_24_16_t res,
+		*bkey = (clib_bihash_kv_24_16_t *) &old_key;
+
+	      if (!clib_bihash_search_24_16 (&im->tun6_protect_by_key, bkey,
+					     &res))
+		{
+		  clib_bihash_add_del_24_16 (&im->tun6_protect_by_key, &res,
+					     0);
+		  clib_memcpy (&res.key, &new_key.key, 3);
+		  clib_bihash_add_del_24_16 (&im->tun6_protect_by_key, &res,
+					     1);
+		}
+	    }
+	}
+      tunnel_unresolve (&sa->tunnel);
+      tunnel_copy (tun, &sa->tunnel);
+      if (!ipsec_sa_is_set_IS_INBOUND (sa))
+	{
+	  dpo_reset (&sa->dpo);
+
+	  sa->tunnel_flags = sa->tunnel.t_encap_decap_flags;
+
+	  rv = tunnel_resolve (&sa->tunnel, FIB_NODE_TYPE_IPSEC_SA, sa_index);
+
+	  if (rv)
+	    {
+	      hash_unset (im->sa_index_by_sa_id, sa->id);
+	      pool_put (ipsec_sa_pool, sa);
+	      return rv;
+	    }
+	  ipsec_sa_stack (sa);
+	  /* generate header templates */
+	  if (ipsec_sa_is_set_IS_TUNNEL_V6 (sa))
+	    {
+	      tunnel_build_v6_hdr (&sa->tunnel,
+				   (ipsec_sa_is_set_UDP_ENCAP (sa) ?
+					    IP_PROTOCOL_UDP :
+					    IP_PROTOCOL_IPSEC_ESP),
+				   &sa->ip6_hdr);
+	    }
+	  else
+	    {
+	      tunnel_build_v4_hdr (&sa->tunnel,
+				   (ipsec_sa_is_set_UDP_ENCAP (sa) ?
+					    IP_PROTOCOL_UDP :
+					    IP_PROTOCOL_IPSEC_ESP),
+				   &sa->ip4_hdr);
+	    }
+	}
+    }
+
+  if (ipsec_sa_is_set_UDP_ENCAP (sa))
+    {
+      if (dst_port != IPSEC_UDP_PORT_NONE &&
+	  dst_port != clib_net_to_host_u16 (sa->udp_hdr.dst_port))
+	{
+	  if (ipsec_sa_is_set_IS_INBOUND (sa))
+	    {
+	      ipsec_unregister_udp_port (
+		clib_net_to_host_u16 (sa->udp_hdr.dst_port),
+		!ipsec_sa_is_set_IS_TUNNEL_V6 (sa));
+	      ipsec_register_udp_port (dst_port,
+				       !ipsec_sa_is_set_IS_TUNNEL_V6 (sa));
+	    }
+	  sa->udp_hdr.dst_port = clib_host_to_net_u16 (dst_port);
+	}
+      if (src_port != IPSEC_UDP_PORT_NONE &&
+	  src_port != clib_net_to_host_u16 (sa->udp_hdr.src_port))
+	sa->udp_hdr.src_port = clib_host_to_net_u16 (src_port);
+    }
+  return (0);
+}
+
+int
 ipsec_sa_add_and_lock (u32 id, u32 spi, ipsec_protocol_t proto,
 		       ipsec_crypto_alg_t crypto_alg, const ipsec_key_t *ck,
 		       ipsec_integ_alg_t integ_alg, const ipsec_key_t *ik,
diff --git a/src/vnet/ipsec/ipsec_sa.h b/src/vnet/ipsec/ipsec_sa.h
index 057e8cd9bff..df079b13872 100644
--- a/src/vnet/ipsec/ipsec_sa.h
+++ b/src/vnet/ipsec/ipsec_sa.h
@@ -270,6 +270,8 @@ extern vlib_simple_counter_main_t ipsec_sa_lost_counters;
 
 extern void ipsec_mk_key (ipsec_key_t * key, const u8 * data, u8 len);
 
+extern int ipsec_sa_update (u32 id, u16 src_port, u16 dst_port,
+			    const tunnel_t *tun, bool is_tun);
 extern int
 ipsec_sa_add_and_lock (u32 id, u32 spi, ipsec_protocol_t proto,
 		       ipsec_crypto_alg_t crypto_alg, const ipsec_key_t *ck,
diff --git a/src/vnet/ipsec/ipsec_test.c b/src/vnet/ipsec/ipsec_test.c
index f1436193636..16d86427ea7 100644
--- a/src/vnet/ipsec/ipsec_test.c
+++ b/src/vnet/ipsec/ipsec_test.c
@@ -307,6 +307,12 @@ api_ipsec_sad_entry_add_del_v3 (vat_main_t *vat)
 }
 
 static int
+api_ipsec_sad_entry_update (vat_main_t *vat)
+{
+  return -1;
+}
+
+static int
 api_ipsec_tunnel_protect_update (vat_main_t *vat)
 {
   return -1;