summaryrefslogtreecommitdiffstats
path: root/lib/librte_table/rte_table_lpm.h
diff options
context:
space:
mode:
Diffstat (limited to 'lib/librte_table/rte_table_lpm.h')
-rw-r--r--lib/librte_table/rte_table_lpm.h124
1 files changed, 124 insertions, 0 deletions
diff --git a/lib/librte_table/rte_table_lpm.h b/lib/librte_table/rte_table_lpm.h
new file mode 100644
index 00000000..f3033234
--- /dev/null
+++ b/lib/librte_table/rte_table_lpm.h
@@ -0,0 +1,124 @@
+/*-
+ * BSD LICENSE
+ *
+ * Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ * * Neither the name of Intel Corporation nor the names of its
+ * contributors may be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef __INCLUDE_RTE_TABLE_LPM_H__
+#define __INCLUDE_RTE_TABLE_LPM_H__
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @file
+ * RTE Table LPM for IPv4
+ *
+ * This table uses the Longest Prefix Match (LPM) algorithm to uniquely
+ * associate data to lookup keys.
+ *
+ * Use-case: IP routing table. Routes that are added to the table associate a
+ * next hop to an IP prefix. The IP prefix is specified as IP address and depth
+ * and cover for a multitude of lookup keys (i.e. destination IP addresses)
+ * that all share the same data (i.e. next hop). The next hop information
+ * typically contains the output interface ID, the IP address of the next hop
+ * station (which is part of the same IP network the output interface is
+ * connected to) and other flags and counters.
+ *
+ * The LPM primitive only allows associating an 8-bit number (next hop ID) to
+ * an IP prefix, while a routing table can potentially contain thousands of
+ * routes or even more. This means that the same next hop ID (and next hop
+ * information) has to be shared by multiple routes, which makes sense, as
+ * multiple remote networks could be reached through the same next hop.
+ * Therefore, when a route is added or updated, the LPM table has to check
+ * whether the same next hop is already in use before using a new next hop ID
+ * for this route.
+ *
+ * The comparison between different next hops is done for the first
+ * “entry_unique_size” bytes of the next hop information (configurable
+ * parameter), which have to uniquely identify the next hop, therefore the user
+ * has to carefully manage the format of the LPM table entry (i.e. the next
+ * hop information) so that any next hop data that changes value during
+ * run-time (e.g. counters) is placed outside of this area.
+ *
+ ***/
+
+#include <stdint.h>
+
+#include "rte_table.h"
+
+/** LPM table parameters */
+struct rte_table_lpm_params {
+ /** Table name */
+ const char *name;
+
+ /** Maximum number of LPM rules (i.e. IP routes) */
+ uint32_t n_rules;
+
+ /**< Number of tbl8s to allocate. */
+ uint32_t number_tbl8s;
+
+ /**< This field is currently unused. */
+ int flags;
+
+ /** Number of bytes at the start of the table entry that uniquely
+ identify the entry. Cannot be bigger than table entry size. */
+ uint32_t entry_unique_size;
+
+ /** Byte offset within input packet meta-data where lookup key (i.e.
+ the destination IP address) is located. */
+ uint32_t offset;
+};
+
+/** LPM table rule (i.e. route), specified as IP prefix. While the key used by
+the lookup operation is the destination IP address (read from the input packet
+meta-data), the entry add and entry delete operations work with LPM rules, with
+each rule covering for a multitude of lookup keys (destination IP addresses)
+that share the same data (next hop). */
+struct rte_table_lpm_key {
+ /** IP address */
+ uint32_t ip;
+
+ /** IP address depth. The most significant "depth" bits of the IP
+ address specify the network part of the IP address, while the rest of
+ the bits specify the host part of the address and are ignored for the
+ purpose of route specification. */
+ uint8_t depth;
+};
+
+/** LPM table operations */
+extern struct rte_table_ops rte_table_lpm_ops;
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif