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... from http://git.savannah.gnu.org/cgit/lwip/lwip-contrib.git/ into contrib/ subdir, STABLE-2_1_0_RELEASE tag lwIP contrib is now officially frozen TODO: Fix build
249 lines
7.6 KiB
C
249 lines
7.6 KiB
C
/**
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* @file
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* IPv6 static route table.
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*/
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/*
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* Copyright (c) 2015 Nest Labs, Inc.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without modification,
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* are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
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* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
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* SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
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* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
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* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
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* OF SUCH DAMAGE.
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*
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* Author: Pradip De <pradipd@google.com>
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*
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*
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* Please coordinate changes and requests with Pradip De
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* <pradipd@google.com>
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*/
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#include "lwip/opt.h"
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#if LWIP_IPV6 /* don't build if not configured for use in lwipopts.h */
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#include "ip6_route_table.h"
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#include "lwip/def.h"
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#include "lwip/mem.h"
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#include "lwip/netif.h"
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#include "lwip/ip6.h"
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#include "lwip/ip6_addr.h"
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#include "lwip/nd6.h"
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#include "lwip/debug.h"
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#include "lwip/stats.h"
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#include "string.h"
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static struct ip6_route_entry static_route_table[LWIP_IPV6_NUM_ROUTE_ENTRIES];
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/**
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* Add the ip6 prefix route and target netif into the static route table while
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* keeping all entries sorted in decreasing order of prefix length.
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* 1. Search from the last entry up to find the correct slot to insert while
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* moving entries one position down to create room.
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* 2. Insert into empty slot created.
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*
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* Subsequently, a linear search down the list can be performed to retrieve a
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* matching route entry for a Longest Prefix Match.
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*
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* @param ip6_prefix the route prefix entry to add.
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* @param netif pointer to target netif.
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* @param gateway the gateway address to use to send through. Has to be link local.
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* @param idx return value argument of index where route entry was added in table.
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* @return ERR_OK if addition was successful.
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* ERR_MEM if table is already full.
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* ERR_ARG if passed argument is bad or route already exists in table.
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*/
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err_t
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ip6_add_route_entry(const struct ip6_prefix *ip6_prefix, struct netif *netif, const ip6_addr_t *gateway, s8_t *idx)
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{
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s8_t i = -1;
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err_t retval = ERR_OK;
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if (!ip6_prefix_valid(ip6_prefix->prefix_len) || (netif == NULL)) {
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retval = ERR_ARG;
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goto exit;
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}
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/* Check if an entry already exists with matching prefix; If so, replace it. */
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for (i = 0; i < LWIP_IPV6_NUM_ROUTE_ENTRIES; i++) {
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if ((ip6_prefix->prefix_len == static_route_table[i].prefix.prefix_len) &&
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memcmp(&ip6_prefix->addr, &static_route_table[i].prefix.addr,
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ip6_prefix->prefix_len / 8) == 0) {
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/* Prefix matches; replace the netif with the one being added. */
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goto insert;
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}
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}
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/* Check if the table is full */
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if (static_route_table[LWIP_IPV6_NUM_ROUTE_ENTRIES - 1].netif != NULL) {
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retval = ERR_MEM;
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goto exit;
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}
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/* Shift all entries down the table until slot is found */
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for (i = LWIP_IPV6_NUM_ROUTE_ENTRIES - 1;
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i > 0 && (ip6_prefix->prefix_len > static_route_table[i - 1].prefix.prefix_len); i--) {
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SMEMCPY(&static_route_table[i], &static_route_table[i - 1], sizeof(struct ip6_route_entry));
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}
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insert:
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/* Insert into the slot selected */
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SMEMCPY(&static_route_table[i].prefix, ip6_prefix, sizeof(struct ip6_prefix));
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static_route_table[i].netif = netif;
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/* Add gateway to route table */
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static_route_table[i].gateway = gateway;
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if (idx != NULL) {
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*idx = i;
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}
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exit:
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return retval;
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}
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/**
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* Removes the route entry from the static route table.
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*
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* @param ip6_prefix the route prefix entry to delete.
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*/
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void
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ip6_remove_route_entry(const struct ip6_prefix *ip6_prefix)
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{
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int i, pos = -1;
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for (i = 0; i < LWIP_IPV6_NUM_ROUTE_ENTRIES; i++) {
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/* compare prefix to find position to delete */
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if (ip6_prefix->prefix_len == static_route_table[i].prefix.prefix_len &&
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memcmp(&ip6_prefix->addr, &static_route_table[i].prefix.addr,
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ip6_prefix->prefix_len / 8) == 0) {
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pos = i;
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break;
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}
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}
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if (pos >= 0) {
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/* Shift everything beyond pos one slot up */
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for (i = pos; i < LWIP_IPV6_NUM_ROUTE_ENTRIES - 1; i++) {
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SMEMCPY(&static_route_table[i], &static_route_table[i+1], sizeof(struct ip6_route_entry));
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if (static_route_table[i].netif == NULL) {
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break;
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}
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}
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/* Zero the remaining entries */
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for (; i < LWIP_IPV6_NUM_ROUTE_ENTRIES; i++) {
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ip6_addr_set_zero((&static_route_table[i].prefix.addr));
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static_route_table[i].netif = NULL;
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}
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}
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}
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/**
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* Finds the appropriate route entry in the static route table corresponding to the given
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* destination IPv6 address. Since the entries in the route table are kept sorted in decreasing
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* order of prefix length, a linear search down the list is performed to retrieve a matching
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* index.
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*
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* @param ip6_dest_addr the destination address to match
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* @return the idx of the found route entry; -1 if not found.
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*/
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s8_t
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ip6_find_route_entry(const ip6_addr_t *ip6_dest_addr)
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{
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s8_t i, idx = -1;
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/* Search prefix in the sorted(decreasing order of prefix length) list */
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for(i = 0; i < LWIP_IPV6_NUM_ROUTE_ENTRIES; i++) {
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if (memcmp(ip6_dest_addr, &static_route_table[i].prefix.addr,
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static_route_table[i].prefix.prefix_len / 8) == 0) {
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idx = i;
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break;
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}
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}
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return idx;
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}
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/**
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* Finds the appropriate network interface for a given IPv6 address from a routing table with
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* static IPv6 routes.
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*
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* @param src the source IPv6 address, if known
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* @param dest the destination IPv6 address for which to find the route
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* @return the netif on which to send to reach dest
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*/
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struct netif *
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ip6_static_route(const ip6_addr_t *src, const ip6_addr_t *dest)
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{
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int i;
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LWIP_UNUSED_ARG(src);
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/* Perform table lookup */
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i = ip6_find_route_entry(dest);
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if (i >= 0) {
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return static_route_table[i].netif;
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} else {
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return NULL;
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}
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}
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/**
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* Finds the gateway IP6 address for a given destination IPv6 address and target netif
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* from a routing table with static IPv6 routes.
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*
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* @param netif the netif used for sending
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* @param dest the destination IPv6 address
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* @return the ip6 address of the gateway to forward packet to
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*/
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const ip6_addr_t *
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ip6_get_gateway(struct netif *netif, const ip6_addr_t *dest)
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{
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const ip6_addr_t *ret_gw = NULL;
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const int i = ip6_find_route_entry(dest);
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LWIP_UNUSED_ARG(netif);
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if (i >= 0) {
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if (static_route_table[i].gateway != NULL) {
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ret_gw = static_route_table[i].gateway;
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}
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}
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return ret_gw;
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}
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/**
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* Returns the top of the route table.
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* This should be used for debug printing only.
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*
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* @return the top of the route table.
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*/
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const struct ip6_route_entry *
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ip6_get_route_table(void)
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{
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return static_route_table;
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}
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#endif /* LWIP_IPV6 */
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