3 files changed, 385 insertions, 0 deletions
diff --git a/contrib/addons/ipv6_static_routing/README b/contrib/addons/ipv6_static_routing/README
new file mode 100644
index 00000000000..0c3b06cc08f
--- /dev/null
+++ b/contrib/addons/ipv6_static_routing/README
@@ -0,0 +1,43 @@
+A simple routing table implementation for addition, deletion and lookup of IPv6 routes. 
+
+APIs are:
+1) s8_t ip6_add_route_entry(struct ip6_prefix *ip6_prefix,
+                            struct netif *netif,
+                            ip6_addr_t *gateway,
+                            s8_t *index);
+
+2) err_t ip6_remove_route_entry(struct ip6_prefix *ip6_prefix);
+
+3) s8_t ip6_find_route_entry(ip6_addr_t *ip6_dest_addr);
+
+4) struct netif *ip6_static_route(ip6_addr_t *src, ip6_addr_t *dest);
+
+5) ip6_addr_t *ip6_get_gateway(struct netif *netif, ip6_addr_t *dest);
+
+6) struct ip6_route_entry *ip6_get_route_table(void);
+
+For route lookup from the table, The LWIP_HOOK_IP6_ROUTE hook in ip6_route(..) of ip6.c
+could be assigned to the ip6_static_route() API of this implementation to return the 
+appropriate netif.
+
+-- The application can add routes using the API ip6_add_route_entry(..). 
+   This API adds the ip6 prefix route into the static route table while
+   keeping all entries sorted in decreasing order of prefix length.
+   Subsequently, a linear search down the list can be performed to retrieve a
+   matching route entry for a Longest Prefix Match.
+   The prefix length is expected to be at an 8-bit boundary. While this is 
+   a limitation, it would serve most practical purposes.
+
+-- The application can remove routes using the API ip6_remove_route_entry(..).
+
+-- The application can find a route entry for a specific address using the 
+   ip6_find_route_entry() function which returns the index of the found entry. 
+   This is used internally by the route lookup function ip6_static_route() API.
+
+-- To fetch the gateway IPv6 address for a specific destination IPv6 
+   address and target netif, the application can call ip6_get_gateway(..).
+   This API could be assigned to the LWIP_HOOK_ND6_GET_GW() if a gateway has
+   been added as part of the ip6_add_route_entry().
+
+-- To fetch a pointer to the head of the table, the application can call 
+   ip6_get_route_table().
diff --git a/contrib/addons/ipv6_static_routing/ip6_route_table.c b/contrib/addons/ipv6_static_routing/ip6_route_table.c
new file mode 100644
index 00000000000..a92dd33706d
--- /dev/null
+++ b/contrib/addons/ipv6_static_routing/ip6_route_table.c
@@ -0,0 +1,248 @@
+/**
+ * @file
+ * IPv6 static route table.
+ */
+
+/*
+ * Copyright (c) 2015 Nest Labs, Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. 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.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
+ *
+ * Author: Pradip De <pradipd@google.com>
+ *
+ *
+ * Please coordinate changes and requests with Pradip De
+ * <pradipd@google.com>
+ */
+
+#include "lwip/opt.h"
+
+#if LWIP_IPV6  /* don't build if not configured for use in lwipopts.h */
+
+#include "ip6_route_table.h"
+#include "lwip/def.h"
+#include "lwip/mem.h"
+#include "lwip/netif.h"
+#include "lwip/ip6.h"
+#include "lwip/ip6_addr.h"
+#include "lwip/nd6.h"
+#include "lwip/debug.h"
+#include "lwip/stats.h"
+
+#include "string.h"
+
+static struct ip6_route_entry static_route_table[LWIP_IPV6_NUM_ROUTE_ENTRIES];
+
+/**
+ * Add the ip6 prefix route and target netif into the static route table while
+ * keeping all entries sorted in decreasing order of prefix length.
+ * 1. Search from the last entry up to find the correct slot to insert while
+ *    moving entries one position down to create room.
+ * 2. Insert into empty slot created.
+ *
+ * Subsequently, a linear search down the list can be performed to retrieve a
+ * matching route entry for a Longest Prefix Match.
+ *
+ * @param ip6_prefix the route prefix entry to add.
+ * @param netif pointer to target netif.
+ * @param gateway the gateway address to use to send through. Has to be link local.
+ * @param idx return value argument of index where route entry was added in table.
+ * @return ERR_OK  if addition was successful.
+ *         ERR_MEM if table is already full.
+ *         ERR_ARG if passed argument is bad or route already exists in table.
+ */
+err_t
+ip6_add_route_entry(const struct ip6_prefix *ip6_prefix, struct netif *netif, const ip6_addr_t *gateway, s8_t *idx)
+{
+  s8_t i = -1;
+  err_t retval = ERR_OK;
+
+  if (!ip6_prefix_valid(ip6_prefix->prefix_len) || (netif == NULL)) {
+    retval = ERR_ARG;
+    goto exit;
+  }
+
+  /* Check if an entry already exists with matching prefix; If so, replace it. */
+  for (i = 0; i < LWIP_IPV6_NUM_ROUTE_ENTRIES; i++) {
+    if ((ip6_prefix->prefix_len == static_route_table[i].prefix.prefix_len) &&
+        memcmp(&ip6_prefix->addr, &static_route_table[i].prefix.addr,
+               ip6_prefix->prefix_len / 8) == 0) {
+      /* Prefix matches; replace the netif with the one being added. */
+      goto insert;
+    }
+  }
+
+  /* Check if the table is full */
+  if (static_route_table[LWIP_IPV6_NUM_ROUTE_ENTRIES - 1].netif != NULL) {
+    retval = ERR_MEM;
+    goto exit;
+  }
+
+  /* Shift all entries down the table until slot is found */
+  for (i = LWIP_IPV6_NUM_ROUTE_ENTRIES - 1;
+       i > 0 && (ip6_prefix->prefix_len > static_route_table[i - 1].prefix.prefix_len); i--) {
+    SMEMCPY(&static_route_table[i], &static_route_table[i - 1], sizeof(struct ip6_route_entry));
+  }
+
+insert:
+  /* Insert into the slot selected */
+  SMEMCPY(&static_route_table[i].prefix, ip6_prefix, sizeof(struct ip6_prefix));
+  static_route_table[i].netif = netif;
+
+  /* Add gateway to route table */
+  static_route_table[i].gateway = gateway;
+
+  if (idx != NULL) {
+    *idx = i;
+  }
+
+exit:
+  return retval;
+}
+
+/**
+ * Removes the route entry from the static route table.
+ *
+ * @param ip6_prefix the route prefix entry to delete.
+ */
+void
+ip6_remove_route_entry(const struct ip6_prefix *ip6_prefix)
+{
+  int i, pos = -1;
+
+  for (i = 0; i < LWIP_IPV6_NUM_ROUTE_ENTRIES; i++) {
+    /* compare prefix to find position to delete */
+    if (ip6_prefix->prefix_len == static_route_table[i].prefix.prefix_len &&
+        memcmp(&ip6_prefix->addr, &static_route_table[i].prefix.addr,
+               ip6_prefix->prefix_len / 8) == 0) {
+      pos = i;
+      break;
+    }
+  }
+
+  if (pos >= 0) {
+    /* Shift everything beyond pos one slot up */
+    for (i = pos; i < LWIP_IPV6_NUM_ROUTE_ENTRIES - 1; i++) {
+      SMEMCPY(&static_route_table[i], &static_route_table[i+1], sizeof(struct ip6_route_entry));
+      if (static_route_table[i].netif == NULL) {
+        break;
+      }
+    }
+    /* Zero the remaining entries */
+    for (; i < LWIP_IPV6_NUM_ROUTE_ENTRIES; i++) {
+      ip6_addr_set_zero((&static_route_table[i].prefix.addr));
+      static_route_table[i].netif = NULL;
+    }
+  }
+}
+
+/**
+ * Finds the appropriate route entry in the static route table corresponding to the given
+ * destination IPv6 address. Since the entries in the route table are kept sorted in decreasing
+ * order of prefix length, a linear search down the list is performed to retrieve a matching
+ * index.
+ *
+ * @param ip6_dest_addr the destination address to match
+ * @return the idx of the found route entry; -1 if not found.
+ */
+s8_t
+ip6_find_route_entry(const ip6_addr_t *ip6_dest_addr)
+{
+  s8_t i, idx = -1;
+
+  /* Search prefix in the sorted(decreasing order of prefix length) list */
+  for(i = 0; i < LWIP_IPV6_NUM_ROUTE_ENTRIES; i++) {
+    if (memcmp(ip6_dest_addr, &static_route_table[i].prefix.addr,
+        static_route_table[i].prefix.prefix_len / 8) == 0) {
+      idx = i;
+      break;
+    }
+  }
+
+  return idx;
+}
+
+/**
+ * Finds the appropriate network interface for a given IPv6 address from a routing table with
+ * static IPv6 routes.
+ *
+ * @param src the source IPv6 address, if known
+ * @param dest the destination IPv6 address for which to find the route
+ * @return the netif on which to send to reach dest
+ */
+struct netif *
+ip6_static_route(const ip6_addr_t *src, const ip6_addr_t *dest)
+{
+  int i;
+
+  LWIP_UNUSED_ARG(src);
+
+  /* Perform table lookup */
+  i = ip6_find_route_entry(dest);
+
+  if (i >= 0) {
+    return static_route_table[i].netif;
+  } else {
+    return NULL;
+  }
+}
+
+/**
+ * Finds the gateway IP6 address for a given destination IPv6 address and target netif
+ * from a routing table with static IPv6 routes.
+ *
+ * @param netif the netif used for sending
+ * @param dest the destination IPv6 address
+ * @return the ip6 address of the gateway to forward packet to
+ */
+const ip6_addr_t *
+ip6_get_gateway(struct netif *netif, const ip6_addr_t *dest)
+{
+  const ip6_addr_t *ret_gw = NULL;
+  const int i = ip6_find_route_entry(dest);
+
+  LWIP_UNUSED_ARG(netif);
+
+  if (i >= 0) {
+    if (static_route_table[i].gateway != NULL) {
+      ret_gw = static_route_table[i].gateway;
+    }
+  }
+
+  return ret_gw;
+}
+
+/**
+ * Returns the top of the route table.
+ * This should be used for debug printing only.
+ *
+ * @return the top of the route table.
+ */
+const struct ip6_route_entry *
+ip6_get_route_table(void)
+{
+    return static_route_table;
+}
+
+#endif /* LWIP_IPV6 */
diff --git a/contrib/addons/ipv6_static_routing/ip6_route_table.h b/contrib/addons/ipv6_static_routing/ip6_route_table.h
new file mode 100644
index 00000000000..478328e47d7
--- /dev/null
+++ b/contrib/addons/ipv6_static_routing/ip6_route_table.h
@@ -0,0 +1,94 @@
+/**
+ * @file
+ *
+ * IPv6 static route table.
+ */
+
+/*
+ * Copyright (c) 2015 Nest Labs, Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. 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.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
+ *
+ * Author: Pradip De <pradipd@google.com>
+ *
+ *
+ * Please coordinate changes and requests with Pradip De
+ * <pradipd@google.com>
+ */
+
+#ifndef __LWIP_IP6_ROUTE_TABLE_H__
+#define __LWIP_IP6_ROUTE_TABLE_H__
+
+#include "lwip/opt.h"
+
+#if LWIP_IPV6  /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/ip6_addr.h"
+#include "lwip/err.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct netif;
+
+/**
+ * LWIP_IPV6_NUM_ROUTES: Number of IPV6 routes that can be kept in the static route table.
+ */
+#ifndef LWIP_IPV6_NUM_ROUTE_ENTRIES
+#define LWIP_IPV6_NUM_ROUTE_ENTRIES         (8)
+#endif
+
+#define IP6_MAX_PREFIX_LEN                  (128)
+#define IP6_PREFIX_ALLOWED_GRANULARITY      (8)
+/* Prefix length cannot be greater than 128 bits and needs to be at a byte boundary */
+#define ip6_prefix_valid(prefix_len)        (((prefix_len) <= IP6_MAX_PREFIX_LEN) &&                 \
+                                             (((prefix_len) % IP6_PREFIX_ALLOWED_GRANULARITY) == 0))
+
+struct ip6_prefix {
+  ip6_addr_t addr;
+  u8_t prefix_len; /* prefix length in bits at byte boundaries */
+};
+
+struct ip6_route_entry {
+  struct ip6_prefix prefix;
+  struct netif *netif;
+  const ip6_addr_t *gateway;
+};
+
+err_t ip6_add_route_entry(const struct ip6_prefix *ip6_prefix, struct netif *netif,
+                          const ip6_addr_t *gateway, s8_t *idx);
+void ip6_remove_route_entry(const struct ip6_prefix *ip6_prefix);
+s8_t ip6_find_route_entry(const ip6_addr_t *ip6_dest_addr);
+struct netif *ip6_static_route(const ip6_addr_t *src, const ip6_addr_t *dest);
+const ip6_addr_t *ip6_get_gateway(struct netif *netif, const ip6_addr_t *dest);
+const struct ip6_route_entry *ip6_get_route_table(void);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* LWIP_IPV6 */
+
+#endif /* __LWIP_IP6_ROUTE_TABLE_H__ */