fib: Decouple source from priority and behaviour

Type: feature

the fib_source_t enum alone no longer defines the priority and
behaviour, instead each source must be allocated these attributes.
This allows the creation of other sources by the plugins (and
soon over the API).

Signed-off-by: Neale Ranns <nranns@cisco.com>
Change-Id: I890ee820fbc16079ee417ea1fbc163192806e853

1 files changed, 302 insertions, 0 deletions

diff --git a/src/vnet/fib/fib_source.h b/src/vnet/fib/fib_source.h
new file mode 100644
index 00000000000..198ef194e2b
--- /dev/null
+++ b/src/vnet/fib/fib_source.h
@@ -0,0 +1,302 @@
+/*
+ * Copyright (c) 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.
+ */
+
+#ifndef __FIB_SOURCE_H__
+#define __FIB_SOURCE_H__
+
+#include <vnet/vnet.h>
+
+/**
+ * The different sources that can create a route.
+ * The sources are defined here with their relative priority order.
+ * The lower the value the higher the priority
+ */
+typedef enum fib_source_t_ {
+    /**
+     * An invalid source
+     * This is not a real source, so don't use it to source a prefix.
+     * It exists here to provide a value for inexistant/uninitialized source
+     */
+    FIB_SOURCE_INVALID = 0,
+    /**
+     * Marker. Add new values after this one.
+     */
+    FIB_SOURCE_FIRST,
+    /**
+     * Special sources. These are for entries that are added to all
+     * FIBs by default, and should never be over-ridden (hence they
+     * are the highest priority)
+     */
+    FIB_SOURCE_SPECIAL = FIB_SOURCE_FIRST,
+    /**
+     * Classify. A route that links directly to a classify adj
+     */
+    FIB_SOURCE_CLASSIFY,
+    /**
+     * A route the is being 'proxied' on behalf of another device
+     */
+    FIB_SOURCE_PROXY,
+    /**
+     * Route added as a result of interface configuration.
+     * this will also come from the API/CLI, but the distinction is
+     * that is from confiiguration on an interface, not a 'ip route' command
+     */
+    FIB_SOURCE_INTERFACE,
+    /**
+     * SRv6 and SR-MPLS
+     */
+    FIB_SOURCE_SR,
+    /**
+     * From the BIER subsystem
+     */
+    FIB_SOURCE_BIER,
+    /**
+     * From 6RD.
+     */
+    FIB_SOURCE_6RD,
+    /**
+     * From the control plane API
+     */
+    FIB_SOURCE_API,
+    /**
+     * From the CLI.
+     */
+    FIB_SOURCE_CLI,
+    /**
+     * LISP
+     */
+    FIB_SOURCE_LISP,
+    /**
+     * IPv[46] Mapping
+     */
+    FIB_SOURCE_MAP,
+    /**
+     * DHCP
+     */
+    FIB_SOURCE_DHCP,
+    /**
+     * IPv6 Proxy ND
+     */
+    FIB_SOURCE_IP6_ND_PROXY,
+    /**
+     * IPv6 ND (seen in the link-local tables)
+     */
+    FIB_SOURCE_IP6_ND,
+    /**
+     * Adjacency source.
+     * routes created as a result of ARP/ND entries. This is lower priority
+     * then the API/CLI. This is on purpose. trust me.
+     */
+    FIB_SOURCE_ADJ,
+    /**
+     * MPLS label. The prefix has been assigned a local label. This source
+     * never provides forwarding information, instead it acts as a place-holder
+     * so the association of label to prefix can be maintained
+     */
+    FIB_SOURCE_MPLS,
+    /**
+     * Attached Export source.
+     * routes created as a result of attahced export. routes thus sourced
+     * will be present in the export tables
+     */
+    FIB_SOURCE_AE,
+    /**
+     * Recursive resolution source.
+     * Used to install an entry that is the resolution traget of another.
+     */
+    FIB_SOURCE_RR,
+    /**
+     * uRPF bypass/exemption.
+     * Used to install an entry that is exempt from the loose uRPF check
+     */
+    FIB_SOURCE_URPF_EXEMPT,
+    /**
+     * The default route source.
+     * The default route is always added to the FIB table (like the
+     * special sources) but we need to be able to over-ride it with
+     * 'ip route' sources when provided
+     */
+    FIB_SOURCE_DEFAULT_ROUTE,
+    /**
+     * The interpose source.
+     * This is not a real source, so don't use it to source a prefix.
+     * It exists here to provide a value against which to register to the
+     * VFT for providing the interpose actions to a real source.
+     */
+    FIB_SOURCE_INTERPOSE,
+    /**
+     * Marker. add new entries before this one.
+     */
+    FIB_SOURCE_LAST = FIB_SOURCE_INTERPOSE,
+} __attribute__ ((packed)) fib_source_t;
+
+STATIC_ASSERT (sizeof(fib_source_t) == 1,
+	       "FIB too many sources");
+
+#define FIB_SOURCES {					\
+    [FIB_SOURCE_INVALID] = "invalid",			\
+    [FIB_SOURCE_SPECIAL] = "special",			\
+    [FIB_SOURCE_INTERFACE] = "interface",		\
+    [FIB_SOURCE_PROXY] = "proxy",                       \
+    [FIB_SOURCE_BIER] = "BIER",			        \
+    [FIB_SOURCE_6RD] = "6RD",			        \
+    [FIB_SOURCE_API] = "API",			        \
+    [FIB_SOURCE_CLI] = "CLI",			        \
+    [FIB_SOURCE_ADJ] = "adjacency",			\
+    [FIB_SOURCE_MAP] = "MAP",			        \
+    [FIB_SOURCE_SR] = "SR",			        \
+    [FIB_SOURCE_LISP] = "LISP", 			\
+    [FIB_SOURCE_CLASSIFY] = "classify",			\
+    [FIB_SOURCE_DHCP] = "DHCP",   			\
+    [FIB_SOURCE_IP6_ND_PROXY] = "IPv6-proxy-nd",        \
+    [FIB_SOURCE_IP6_ND] = "IPv6-nd",                    \
+    [FIB_SOURCE_RR] = "recursive-resolution",	        \
+    [FIB_SOURCE_AE] = "attached_export",	        \
+    [FIB_SOURCE_MPLS] = "mpls",           	        \
+    [FIB_SOURCE_URPF_EXEMPT] = "urpf-exempt",	        \
+    [FIB_SOURCE_DEFAULT_ROUTE] = "default-route",	\
+    [FIB_SOURCE_INTERPOSE] = "interpose",               \
+}
+
+/**
+ * Each source is assigned a priority. lower priority is beeter.
+ * the source with the best source with have its contribution added
+ * to forwarding. the lesser sources will be 'remembered' by FIB and
+ * added to forwarding should the best source be removed.
+ */
+typedef u8 fib_source_priority_t;
+
+/**
+ * source comparison
+ */
+typedef enum fib_source_priority_cmp_t_
+{
+    FIB_SOURCE_CMP_BETTER,
+    FIB_SOURCE_CMP_WORSE,
+    FIB_SOURCE_CMP_EQUAL,
+} fib_source_priority_cmp_t;
+
+/**
+ * Each source has a defined behaviour that controls how entries
+ * behave that have that source
+ */
+typedef enum fib_source_behaviour_t_
+{
+    /**
+     * If your adding a new source from a plugin pick one of these
+     */
+    /** Default behaviour - always install a drop */
+    FIB_SOURCE_BH_DROP,
+    /** add paths with [mpls] path extensions */
+    FIB_SOURCE_BH_API,
+    /** add paths without path extensions */
+    FIB_SOURCE_BH_SIMPLE,
+
+    /**
+     * If your adding a new source from a plugin
+     * these are probably not the behaviour you're lokking for.
+     */
+    /** recursive resolution w/ cover tracking*/
+    FIB_SOURCE_BH_RR,
+    /** associated label stored in private data */
+    FIB_SOURCE_BH_MPLS,
+    /** cover tracking w/ glean management */
+    FIB_SOURCE_BH_INTERFACE,
+    /** interpose */
+    FIB_SOURCE_BH_INTERPOSE,
+    /** simple + source fib tracking */
+    FIB_SOURCE_BH_LISP,
+    /** adj w/ cover tracking + refinement */
+    FIB_SOURCE_BH_ADJ,
+} fib_source_behaviour_t;
+
+#define FIB_SOURCE_BH_MAX (FIB_SOURCE_BH_ADJ+1)
+
+#define FIB_SOURCE_BEHAVIOURS {                 \
+    [FIB_SOURCE_BH_DROP] = "drop",		\
+    [FIB_SOURCE_BH_RR] = "rr",                  \
+    [FIB_SOURCE_BH_MPLS] = "mpls",              \
+    [FIB_SOURCE_BH_INTERFACE] = "interface",    \
+    [FIB_SOURCE_BH_INTERPOSE] = "interpose",    \
+    [FIB_SOURCE_BH_LISP] = "lisp",              \
+    [FIB_SOURCE_BH_ADJ] = "adjacency",          \
+    [FIB_SOURCE_BH_API] = "api",                \
+    [FIB_SOURCE_BH_SIMPLE] = "simple",          \
+}
+
+/**
+ * The fixed source to priority mappings.
+ * Declared here so those adding new sources can better determine their respective
+ * priority values.
+ */
+#define foreach_fib_source                                      \
+    /** you can't do better then the special source */         \
+    _(FIB_SOURCE_SPECIAL,       0x00, FIB_SOURCE_BH_SIMPLE)    \
+    _(FIB_SOURCE_CLASSIFY,      0x01, FIB_SOURCE_BH_SIMPLE)    \
+    _(FIB_SOURCE_PROXY,         0x02, FIB_SOURCE_BH_SIMPLE)    \
+    _(FIB_SOURCE_INTERFACE,     0x03, FIB_SOURCE_BH_INTERFACE) \
+    _(FIB_SOURCE_SR,            0x10, FIB_SOURCE_BH_API)       \
+    _(FIB_SOURCE_BIER,          0x20, FIB_SOURCE_BH_SIMPLE)    \
+    _(FIB_SOURCE_6RD,           0x30, FIB_SOURCE_BH_API)       \
+    _(FIB_SOURCE_API,           0x80, FIB_SOURCE_BH_API)       \
+    _(FIB_SOURCE_CLI,           0x81, FIB_SOURCE_BH_API)       \
+    _(FIB_SOURCE_LISP,          0x90, FIB_SOURCE_BH_LISP)      \
+    _(FIB_SOURCE_MAP,           0xa0, FIB_SOURCE_BH_SIMPLE)    \
+    _(FIB_SOURCE_DHCP,          0xb0, FIB_SOURCE_BH_API)       \
+    _(FIB_SOURCE_IP6_ND_PROXY,  0xc0, FIB_SOURCE_BH_API)       \
+    _(FIB_SOURCE_IP6_ND,        0xc1, FIB_SOURCE_BH_API)       \
+    _(FIB_SOURCE_ADJ,           0xd0, FIB_SOURCE_BH_ADJ)       \
+    _(FIB_SOURCE_MPLS,          0xe0, FIB_SOURCE_BH_MPLS)      \
+    _(FIB_SOURCE_AE,            0xf0, FIB_SOURCE_BH_SIMPLE)    \
+    _(FIB_SOURCE_RR,            0xfb, FIB_SOURCE_BH_RR)        \
+    _(FIB_SOURCE_URPF_EXEMPT,   0xfc, FIB_SOURCE_BH_RR)        \
+    _(FIB_SOURCE_DEFAULT_ROUTE, 0xfd, FIB_SOURCE_BH_DROP)      \
+    _(FIB_SOURCE_INTERPOSE,     0xfe, FIB_SOURCE_BH_INTERPOSE) \
+    _(FIB_SOURCE_INVALID,       0xff, FIB_SOURCE_BH_DROP)
+
+/**
+ * Some priority values that plugins might use when they are not to concerned
+ * where in the list they'll go.
+ */
+#define FIB_SOURCE_PRIORITY_HI 0x10
+#define FIB_SOURCE_PRIORITY_LOW 0xd0
+
+
+extern u16 fib_source_get_prio(fib_source_t src);
+extern fib_source_behaviour_t fib_source_get_behaviour(fib_source_t src);
+extern fib_source_priority_cmp_t fib_source_cmp(fib_source_t s1,
+                                                fib_source_t s2);
+
+extern u8 *format_fib_source(u8 *s, va_list *a);
+
+extern fib_source_t fib_source_allocate(const char *name,
+                                        fib_source_priority_t prio,
+                                        fib_source_behaviour_t bh);
+
+extern void fib_source_register(fib_source_t src,
+                                fib_source_priority_t prio,
+                                fib_source_behaviour_t bh);
+
+typedef walk_rc_t (*fib_source_walk_t)(fib_source_t id,
+                                       const char *name,
+                                       fib_source_priority_t prio,
+                                       fib_source_behaviour_t bh,
+                                       void *ctx);
+extern void fib_source_walk(fib_source_walk_t fn,
+                            void *ctx);
+
+extern void fib_source_module_init(void);
+
+#endif