BFD: set per session UDP source port per RFC

Change-Id: Id294dbbd6499ae8221cc8143e1027adc08866ae6
Signed-off-by: Klement Sekera <ksekera@cisco.com>

src/vnet/bfd/bfd_main.c

@@ -35,11 +35,6 @@ bfd_usec_to_clocks (const bfd_main_t * bm, u64 us)
   return bm->cpu_cps * ((f64) us / USEC_PER_SECOND);
 }
 
-// static u64 bfd_clocks_to_usec (const bfd_main_t *bm, u64 clocks)
-//{
-//  return (clocks / bm->cpu_cps) * USEC_PER_SECOND;
-//}
-
 static vlib_node_registration_t bfd_process_node;
 
 /* set to 0 here, real values filled at startup */
@@ -464,11 +459,11 @@ bfd_add_transport_layer (vlib_main_t * vm, vlib_buffer_t * b,
     {
     case BFD_TRANSPORT_UDP4:
       BFD_DBG ("Transport bfd via udp4, bs_idx=%u", bs->bs_idx);
-      bfd_add_udp4_transport (vm, b, &bs->udp);
+      bfd_add_udp4_transport (vm, b, bs);
       break;
     case BFD_TRANSPORT_UDP6:
       BFD_DBG ("Transport bfd via udp6, bs_idx=%u", bs->bs_idx);
-      bfd_add_udp6_transport (vm, b, &bs->udp);
+      bfd_add_udp6_transport (vm, b, bs);
       break;
     }
 }

src/vnet/bfd/bfd_main.h

@@ -76,7 +76,7 @@ typedef enum
 #undef F
 } bfd_poll_state_e;
 
-typedef struct
+typedef struct bfd_session_s
 {
   /* index in bfd_main.sessions pool */
   u32 bs_idx;

src/vnet/bfd/bfd_udp.c

@@ -1,3 +1,17 @@
+/*
+ * Copyright (c) 2011-2016 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
 #include <vppinfra/types.h>
 #include <vlibmemory/api.h>
 #include <vlib/vlib.h>
@@ -31,10 +45,25 @@ static vlib_node_registration_t bfd_udp6_input_node;
 
 bfd_udp_main_t bfd_udp_main;
 
+static u16
+bfd_udp_bs_idx_to_sport (u32 bs_idx)
+{
+  /* The source port MUST be in the range 49152 through 65535. The same UDP
+   * source port number MUST be used for all BFD Control packets associated
+   * with a particular session.  The source port number SHOULD be unique among
+   * all BFD sessions on the system. If more than 16384 BFD sessions are
+   * simultaneously active, UDP source port numbers MAY be reused on
+   * multiple sessions, but the number of distinct uses of the same UDP
+   * source port number SHOULD be minimized.
+   */
+  return 49152 + bs_idx % (65535 - 49152 + 1);
+}
+
 void
 bfd_add_udp4_transport (vlib_main_t * vm, vlib_buffer_t * b,
-			bfd_udp_session_t * bus)
+			const bfd_session_t * bs)
 {
+  const bfd_udp_session_t *bus = &bs->udp;
   const bfd_udp_key_t *key = &bus->key;
 
   b->flags |= VNET_BUFFER_LOCALLY_ORIGINATED;
@@ -55,7 +84,8 @@ bfd_add_udp4_transport (vlib_main_t * vm, vlib_buffer_t * b,
   headers->ip4.src_address.as_u32 = key->local_addr.ip4.as_u32;
   headers->ip4.dst_address.as_u32 = key->peer_addr.ip4.as_u32;
 
-  headers->udp.src_port = clib_host_to_net_u16 (50000);	/* FIXME */
+  headers->udp.src_port =
+    clib_host_to_net_u16 (bfd_udp_bs_idx_to_sport (bs->bs_idx));
   headers->udp.dst_port = clib_host_to_net_u16 (UDP_DST_PORT_bfd4);
 
   /* fix ip length, checksum and udp length */
@@ -70,8 +100,9 @@ bfd_add_udp4_transport (vlib_main_t * vm, vlib_buffer_t * b,
 
 void
 bfd_add_udp6_transport (vlib_main_t * vm, vlib_buffer_t * b,
-			bfd_udp_session_t * bus)
+			const bfd_session_t * bs)
 {
+  const bfd_udp_session_t *bus = &bs->udp;
   const bfd_udp_key_t *key = &bus->key;
 
   b->flags |= VNET_BUFFER_LOCALLY_ORIGINATED;
@@ -95,7 +126,8 @@ bfd_add_udp6_transport (vlib_main_t * vm, vlib_buffer_t * b,
   clib_memcpy (&headers->ip6.dst_address, &key->peer_addr.ip6,
 	       sizeof (headers->ip6.dst_address));
 
-  headers->udp.src_port = clib_host_to_net_u16 (50000);	/* FIXME */
+  headers->udp.src_port =
+    clib_host_to_net_u16 (bfd_udp_bs_idx_to_sport (bs->bs_idx));
   headers->udp.dst_port = clib_host_to_net_u16 (UDP_DST_PORT_bfd6);
 
   /* fix ip payload length and udp length */

src/vnet/bfd/bfd_udp.h

@@ -23,8 +23,6 @@
 #include <vnet/adj/adj_types.h>
 #include <vnet/ip/ip6_packet.h>
 
-#define BFD_UDP_KEY_BODY
-
 /* *INDENT-OFF* */
 typedef CLIB_PACKED (struct {
 
@@ -42,10 +40,12 @@ typedef struct
   adj_index_t adj_index;
 } bfd_udp_session_t;
 
+struct bfd_session_s;
+
 void bfd_add_udp4_transport (vlib_main_t * vm, vlib_buffer_t * b,
-			     bfd_udp_session_t * bs);
+			     const struct bfd_session_s *bs);
 void bfd_add_udp6_transport (vlib_main_t * vm, vlib_buffer_t * b,
-			     bfd_udp_session_t * bs);
+			     const struct bfd_session_s *bs);
 
 #endif /* __included_bfd_udp_h__ */