fib: Source Address Selection

Type: feature

Use the FIB to provide SAS (in so far as it is today)
 - Use the glean adjacency as the record of the connected prefixes
 = there's a glean per-{interface, protocol, connected-prefix}
 - Keep the glean up to date with whatever the recieve host prefix is
(since it can change)

Signed-off-by: Neale Ranns <neale.ranns@cisco.com>
Change-Id: I0f3dd1edb1f3fc965af1c7c586709028eb9cdeac

1 files changed, 75 insertions, 0 deletions

diff --git a/src/vnet/fib/fib_sas.h b/src/vnet/fib/fib_sas.h
new file mode 100644
index 00000000000..172a4d6b2dc
--- /dev/null
+++ b/src/vnet/fib/fib_sas.h
@@ -0,0 +1,75 @@
+/*
+ * Copyright (c) 2020 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.
+ */
+
+/**
+ * @brief FIB Source Address selection
+ *
+ * Use the FIB for source address selection on an interface
+ */
+
+#ifndef __FIB_SAS_H__
+#define __FIB_SAS_H__
+
+#include <vnet/fib/fib_types.h>
+#include <vnet/ip/ip_types.h>
+
+/**
+ * @brief Get a Source address to use in a packet being sent out
+ *        an interface
+ *
+ * @param sw_if_index The interface on which the packet is to be sent
+ * @param af The address family of the packet
+ * @param dst The destination of the packet (can be NULL in which case any
+ *            of the available address will be returned)
+ * @param src OUT the source address to use
+ *
+ * @return True if an address is available False (and src is unset) otherwise
+ */
+extern bool fib_sas_get (u32 sw_if_index,
+                         ip_address_family_t af,
+                         const ip46_address_t *dst,
+                         ip46_address_t *src);
+
+/**
+ * @brief Get an IPv4 Source address to use in a packet being sent out
+ *        an interface
+ *
+ * @param sw_if_index The interface on which the packet is to be sent
+ * @param dst The destination of the packet (can be NULL in which case any
+ *            of the available address will be returned)
+ * @param src OUT the source address to use
+ *
+ * @return True if an address is available False (and src is unset) otherwise
+ */
+extern bool fib_sas4_get (u32 sw_if_index,
+                          const ip4_address_t *dst,
+                          ip4_address_t *src);
+
+/**
+ * @brief Get an IPv6 Source address to use in a packet being sent out
+ *        an interface
+ *
+ * @param sw_if_index The interface on which the packet is to be sent
+ * @param dst The destination of the packet (can be NULL in which case any
+ *            of the available address will be returned)
+ * @param src OUT the source address to use
+ *
+ * @return True if an address is available False (and src is unset) otherwise
+ */
+extern bool fib_sas6_get (u32 sw_if_index,
+                          const ip6_address_t *dst,
+                          ip6_address_t *src);
+
+#endif