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esp-idf/components/lwip/core/ipv6/nd6.c

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Initial public version
2016-08-17 11:08:22 -04:00
/**
* @file
*
* Neighbor discovery and stateless address autoconfiguration for IPv6.
* Aims to be compliant with RFC 4861 (Neighbor discovery) and RFC 4862
* (Address autoconfiguration).
*/
/*
* Copyright (c) 2010 Inico Technologies Ltd.
* 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.
*
* This file is part of the lwIP TCP/IP stack.
*
* Author: Ivan Delamer <delamer@inicotech.com>
*
*
* Please coordinate changes and requests with Ivan Delamer
* <delamer@inicotech.com>
*/
#include "lwip/opt.h"
#if LWIP_IPV6 /* don't build if not configured for use in lwipopts.h */
#include "lwip/nd6.h"
#include "lwip/pbuf.h"
#include "lwip/mem.h"
#include "lwip/memp.h"
#include "lwip/ip6.h"
#include "lwip/ip6_addr.h"
#include "lwip/inet_chksum.h"
#include "lwip/netif.h"
#include "lwip/icmp6.h"
#include "lwip/mld6.h"
#include "lwip/ip.h"
#include "lwip/stats.h"
#include <string.h>
/* Router tables. */
struct nd6_neighbor_cache_entry neighbor_cache[LWIP_ND6_NUM_NEIGHBORS];
struct nd6_destination_cache_entry destination_cache[LWIP_ND6_NUM_DESTINATIONS];
struct nd6_prefix_list_entry prefix_list[LWIP_ND6_NUM_PREFIXES];
struct nd6_router_list_entry default_router_list[LWIP_ND6_NUM_ROUTERS];
/* Default values, can be updated by a RA message. */
u32_t reachable_time = LWIP_ND6_REACHABLE_TIME;
u32_t retrans_timer = LWIP_ND6_RETRANS_TIMER; /* TODO implement this value in timer */
/* Index for cache entries. */
static u8_t nd6_cached_neighbor_index;
static u8_t nd6_cached_destination_index;
/* Multicast address holder. */
static ip6_addr_t multicast_address;
/* Static buffer to parse RA packet options (size of a prefix option, biggest option) */
static u8_t nd6_ra_buffer[sizeof(struct prefix_option)];
/* Forward declarations. */
static s8_t nd6_find_neighbor_cache_entry(const ip6_addr_t * ip6addr);
static s8_t nd6_new_neighbor_cache_entry(void);
static void nd6_free_neighbor_cache_entry(s8_t i);
static s8_t nd6_find_destination_cache_entry(const ip6_addr_t * ip6addr);
static s8_t nd6_new_destination_cache_entry(void);
static s8_t nd6_is_prefix_in_netif(const ip6_addr_t * ip6addr, struct netif * netif);
static s8_t nd6_get_router(const ip6_addr_t * router_addr, struct netif * netif);
static s8_t nd6_new_router(const ip6_addr_t * router_addr, struct netif * netif);
static s8_t nd6_get_onlink_prefix(ip6_addr_t * prefix, struct netif * netif);
static s8_t nd6_new_onlink_prefix(ip6_addr_t * prefix, struct netif * netif);
#define ND6_SEND_FLAG_MULTICAST_DEST 0x01
#define ND6_SEND_FLAG_ALLNODES_DEST 0x02
static void nd6_send_ns(struct netif * netif, const ip6_addr_t * target_addr, u8_t flags);
static void nd6_send_na(struct netif * netif, const ip6_addr_t * target_addr, u8_t flags);
#if LWIP_IPV6_SEND_ROUTER_SOLICIT
static err_t nd6_send_rs(struct netif * netif);
#endif /* LWIP_IPV6_SEND_ROUTER_SOLICIT */
#if LWIP_ND6_QUEUEING
static void nd6_free_q(struct nd6_q_entry *q);
#else /* LWIP_ND6_QUEUEING */
#define nd6_free_q(q) pbuf_free(q)
#endif /* LWIP_ND6_QUEUEING */
static void nd6_send_q(s8_t i);
/**
* Process an incoming neighbor discovery message
*
* @param p the nd packet, p->payload pointing to the icmpv6 header
* @param inp the netif on which this packet was received
*/
void
nd6_input(struct pbuf *p, struct netif *inp)
{
u8_t msg_type;
s8_t i;
ND6_STATS_INC(nd6.recv);
msg_type = *((u8_t *)p->payload);
switch (msg_type) {
case ICMP6_TYPE_NA: /* Neighbor Advertisement. */
{
struct na_header * na_hdr;
struct lladdr_option * lladdr_opt;
/* Check that na header fits in packet. */
if (p->len < (sizeof(struct na_header))) {
/* TODO debug message */
pbuf_free(p);
ND6_STATS_INC(nd6.lenerr);
ND6_STATS_INC(nd6.drop);
return;
}
na_hdr = (struct na_header *)p->payload;
/* Unsolicited NA?*/
if (ip6_addr_ismulticast(ip6_current_dest_addr())) {
/* This is an unsolicited NA.
* link-layer changed?
* part of DAD mechanism? */
/* Check that link-layer address option also fits in packet. */
if (p->len < (sizeof(struct na_header) + 2)) {
/* TODO debug message */
pbuf_free(p);
ND6_STATS_INC(nd6.lenerr);
ND6_STATS_INC(nd6.drop);
return;
}
lladdr_opt = (struct lladdr_option *)((u8_t*)p->payload + sizeof(struct na_header));
if (p->len < (sizeof(struct na_header) + (lladdr_opt->length << 3))) {
/* TODO debug message */
pbuf_free(p);
ND6_STATS_INC(nd6.lenerr);
ND6_STATS_INC(nd6.drop);
return;
}
/* Override ip6_current_dest_addr() so that we have an aligned copy. */
ip6_addr_set(ip6_current_dest_addr(), &(na_hdr->target_address));
#if LWIP_IPV6_DUP_DETECT_ATTEMPTS
/* If the target address matches this netif, it is a DAD response. */
for (i = 0; i < LWIP_IPV6_NUM_ADDRESSES; i++) {
if (!ip6_addr_isinvalid(netif_ip6_addr_state(inp, i)) &&
ip6_addr_cmp(ip6_current_dest_addr(), netif_ip6_addr(inp, i))) {
/* We are using a duplicate address. */
netif_ip6_addr_set_state(inp, i, IP6_ADDR_INVALID);
#if LWIP_IPV6_MLD
/* Leave solicited node multicast group. */
ip6_addr_set_solicitednode(&multicast_address, netif_ip6_addr(inp, i)->addr[3]);
mld6_leavegroup(netif_ip6_addr(inp, i), &multicast_address);
#endif /* LWIP_IPV6_MLD */
#if LWIP_IPV6_AUTOCONFIG
/* Check to see if this address was autoconfigured. */
if (!ip6_addr_islinklocal(ip6_current_dest_addr())) {
i = nd6_get_onlink_prefix(ip6_current_dest_addr(), inp);
if (i >= 0) {
/* Mark this prefix as duplicate, so that we don't use it
* to generate this address again. */
prefix_list[i].flags |= ND6_PREFIX_AUTOCONFIG_ADDRESS_DUPLICATE;
}
}
#endif /* LWIP_IPV6_AUTOCONFIG */
pbuf_free(p);
return;
}
}
#endif /* LWIP_IPV6_DUP_DETECT_ATTEMPTS */
/* This is an unsolicited NA, most likely there was a LLADDR change. */
i = nd6_find_neighbor_cache_entry(ip6_current_dest_addr());
if (i >= 0) {
if (na_hdr->flags & ND6_FLAG_OVERRIDE) {
MEMCPY(neighbor_cache[i].lladdr, lladdr_opt->addr, inp->hwaddr_len);
}
}
} else {
/* This is a solicited NA.
* neighbor address resolution response?
* neighbor unreachability detection response? */
/* Override ip6_current_dest_addr() so that we have an aligned copy. */
ip6_addr_set(ip6_current_dest_addr(), &(na_hdr->target_address));
/* Find the cache entry corresponding to this na. */
i = nd6_find_neighbor_cache_entry(ip6_current_dest_addr());
if (i < 0) {
/* We no longer care about this target address. drop it. */
pbuf_free(p);
return;
}
/* Update cache entry. */
neighbor_cache[i].netif = inp;
neighbor_cache[i].counter.reachable_time = reachable_time;
if ((na_hdr->flags & ND6_FLAG_OVERRIDE) ||
(neighbor_cache[i].state == ND6_INCOMPLETE)) {
/* Check that link-layer address option also fits in packet. */
if (p->len < (sizeof(struct na_header) + 2)) {
/* TODO debug message */
pbuf_free(p);
ND6_STATS_INC(nd6.lenerr);
ND6_STATS_INC(nd6.drop);
return;
}
lladdr_opt = (struct lladdr_option *)((u8_t*)p->payload + sizeof(struct na_header));
if (p->len < (sizeof(struct na_header) + (lladdr_opt->length << 3))) {
/* TODO debug message */
pbuf_free(p);
ND6_STATS_INC(nd6.lenerr);
ND6_STATS_INC(nd6.drop);
return;
}
MEMCPY(neighbor_cache[i].lladdr, lladdr_opt->addr, inp->hwaddr_len);
}
neighbor_cache[i].state = ND6_REACHABLE;
/* Send queued packets, if any. */
if (neighbor_cache[i].q != NULL) {
nd6_send_q(i);
}
}
break; /* ICMP6_TYPE_NA */
}
case ICMP6_TYPE_NS: /* Neighbor solicitation. */
{
struct ns_header * ns_hdr;
struct lladdr_option * lladdr_opt;
u8_t accepted;
/* Check that ns header fits in packet. */
if (p->len < sizeof(struct ns_header)) {
/* TODO debug message */
pbuf_free(p);
ND6_STATS_INC(nd6.lenerr);
ND6_STATS_INC(nd6.drop);
return;
}
ns_hdr = (struct ns_header *)p->payload;
/* Check if there is a link-layer address provided. Only point to it if in this buffer. */
if (p->len >= (sizeof(struct ns_header) + 2)) {
lladdr_opt = (struct lladdr_option *)((u8_t*)p->payload + sizeof(struct ns_header));
if (p->len < (sizeof(struct ns_header) + (lladdr_opt->length << 3))) {
lladdr_opt = NULL;
}
} else {
lladdr_opt = NULL;
}
/* Check if the target address is configured on the receiving netif. */
accepted = 0;
for (i = 0; i < LWIP_IPV6_NUM_ADDRESSES; ++i) {
if ((ip6_addr_isvalid(netif_ip6_addr_state(inp, i)) ||
(ip6_addr_istentative(netif_ip6_addr_state(inp, i)) &&
ip6_addr_isany(ip6_current_src_addr()))) &&
ip6_addr_cmp(&(ns_hdr->target_address), netif_ip6_addr(inp, i))) {
accepted = 1;
break;
}
}
/* NS not for us? */
if (!accepted) {
pbuf_free(p);
return;
}
/* Check for ANY address in src (DAD algorithm). */
if (ip6_addr_isany(ip6_current_src_addr())) {
/* Sender is validating this address. */
for (i = 0; i < LWIP_IPV6_NUM_ADDRESSES; ++i) {
if (!ip6_addr_isinvalid(netif_ip6_addr_state(inp, i)) &&
ip6_addr_cmp(&(ns_hdr->target_address), netif_ip6_addr(inp, i))) {
/* Send a NA back so that the sender does not use this address. */
nd6_send_na(inp, netif_ip6_addr(inp, i), ND6_FLAG_OVERRIDE | ND6_SEND_FLAG_ALLNODES_DEST);
if (ip6_addr_istentative(netif_ip6_addr_state(inp, i))) {
/* We shouldn't use this address either. */
netif_ip6_addr_set_state(inp, i, IP6_ADDR_INVALID);
}
}
}
} else {
/* Sender is trying to resolve our address. */
/* Verify that they included their own link-layer address. */
if (lladdr_opt == NULL) {
/* Not a valid message. */
pbuf_free(p);
ND6_STATS_INC(nd6.proterr);
ND6_STATS_INC(nd6.drop);
return;
}
i = nd6_find_neighbor_cache_entry(ip6_current_src_addr());
if (i>= 0) {
/* We already have a record for the solicitor. */
if (neighbor_cache[i].state == ND6_INCOMPLETE) {
neighbor_cache[i].netif = inp;
MEMCPY(neighbor_cache[i].lladdr, lladdr_opt->addr, inp->hwaddr_len);
/* Delay probe in case we get confirmation of reachability from upper layer (TCP). */
neighbor_cache[i].state = ND6_DELAY;
neighbor_cache[i].counter.delay_time = LWIP_ND6_DELAY_FIRST_PROBE_TIME;
}
} else {
/* Add their IPv6 address and link-layer address to neighbor cache.
* We will need it at least to send a unicast NA message, but most
* likely we will also be communicating with this node soon. */
i = nd6_new_neighbor_cache_entry();
if (i < 0) {
/* We couldn't assign a cache entry for this neighbor.
* we won't be able to reply. drop it. */
pbuf_free(p);
ND6_STATS_INC(nd6.memerr);
return;
}
neighbor_cache[i].netif = inp;
MEMCPY(neighbor_cache[i].lladdr, lladdr_opt->addr, inp->hwaddr_len);
ip6_addr_set(&(neighbor_cache[i].next_hop_address), ip6_current_src_addr());
/* Receiving a message does not prove reachability: only in one direction.
* Delay probe in case we get confirmation of reachability from upper layer (TCP). */
neighbor_cache[i].state = ND6_DELAY;
neighbor_cache[i].counter.delay_time = LWIP_ND6_DELAY_FIRST_PROBE_TIME;
}
/* Override ip6_current_dest_addr() so that we have an aligned copy. */
ip6_addr_set(ip6_current_dest_addr(), &(ns_hdr->target_address));
/* Send back a NA for us. Allocate the reply pbuf. */
nd6_send_na(inp, ip6_current_dest_addr(), ND6_FLAG_SOLICITED | ND6_FLAG_OVERRIDE);
}
break; /* ICMP6_TYPE_NS */
}
case ICMP6_TYPE_RA: /* Router Advertisement. */
{
struct ra_header * ra_hdr;
u8_t * buffer; /* Used to copy options. */
u16_t offset;
/* Check that RA header fits in packet. */
if (p->len < sizeof(struct ra_header)) {
/* TODO debug message */
pbuf_free(p);
ND6_STATS_INC(nd6.lenerr);
ND6_STATS_INC(nd6.drop);
return;
}
ra_hdr = (struct ra_header *)p->payload;
/* If we are sending RS messages, stop. */
#if LWIP_IPV6_SEND_ROUTER_SOLICIT
/* ensure at least one solicitation is sent */
if ((inp->rs_count < LWIP_ND6_MAX_MULTICAST_SOLICIT) ||
(nd6_send_rs(inp) == ERR_OK)) {
inp->rs_count = 0;
}
#endif /* LWIP_IPV6_SEND_ROUTER_SOLICIT */
/* Get the matching default router entry. */
i = nd6_get_router(ip6_current_src_addr(), inp);
if (i < 0) {
/* Create a new router entry. */
i = nd6_new_router(ip6_current_src_addr(), inp);
}
if (i < 0) {
/* Could not create a new router entry. */
pbuf_free(p);
ND6_STATS_INC(nd6.memerr);
return;
}
/* Re-set invalidation timer. */
default_router_list[i].invalidation_timer = htons(ra_hdr->router_lifetime);
/* Re-set default timer values. */
#if LWIP_ND6_ALLOW_RA_UPDATES
if (ra_hdr->retrans_timer > 0) {
retrans_timer = htonl(ra_hdr->retrans_timer);
}
if (ra_hdr->reachable_time > 0) {
reachable_time = htonl(ra_hdr->reachable_time);
}
#endif /* LWIP_ND6_ALLOW_RA_UPDATES */
/* TODO set default hop limit... */
/* ra_hdr->current_hop_limit;*/
/* Update flags in local entry (incl. preference). */
default_router_list[i].flags = ra_hdr->flags;
/* Offset to options. */
offset = sizeof(struct ra_header);
/* Process each option. */
while ((p->tot_len - offset) > 0) {
if (p->len == p->tot_len) {
/* no need to copy from contiguous pbuf */
buffer = &((u8_t*)p->payload)[offset];
} else {
buffer = nd6_ra_buffer;
pbuf_copy_partial(p, buffer, sizeof(struct prefix_option), offset);
}
switch (buffer[0]) {
case ND6_OPTION_TYPE_SOURCE_LLADDR:
{
struct lladdr_option * lladdr_opt;
lladdr_opt = (struct lladdr_option *)buffer;
if ((default_router_list[i].neighbor_entry != NULL) &&
(default_router_list[i].neighbor_entry->state == ND6_INCOMPLETE)) {
SMEMCPY(default_router_list[i].neighbor_entry->lladdr, lladdr_opt->addr, inp->hwaddr_len);
default_router_list[i].neighbor_entry->state = ND6_REACHABLE;
default_router_list[i].neighbor_entry->counter.reachable_time = reachable_time;
}
break;
}
case ND6_OPTION_TYPE_MTU:
{
struct mtu_option * mtu_opt;
mtu_opt = (struct mtu_option *)buffer;
if (htonl(mtu_opt->mtu) >= 1280) {
#if LWIP_ND6_ALLOW_RA_UPDATES
inp->mtu = (u16_t)htonl(mtu_opt->mtu);
#endif /* LWIP_ND6_ALLOW_RA_UPDATES */
}
break;
}
case ND6_OPTION_TYPE_PREFIX_INFO:
{
struct prefix_option * prefix_opt;
prefix_opt = (struct prefix_option *)buffer;
if (prefix_opt->flags & ND6_PREFIX_FLAG_ON_LINK) {
/* Add to on-link prefix list. */
s8_t prefix;
/* Get a memory-aligned copy of the prefix. */
ip6_addr_set(ip6_current_dest_addr(), &(prefix_opt->prefix));
/* find cache entry for this prefix. */
prefix = nd6_get_onlink_prefix(ip6_current_dest_addr(), inp);
if (prefix < 0) {
/* Create a new cache entry. */
prefix = nd6_new_onlink_prefix(ip6_current_dest_addr(), inp);
}
if (prefix >= 0) {
prefix_list[prefix].invalidation_timer = htonl(prefix_opt->valid_lifetime);
#if LWIP_IPV6_AUTOCONFIG
if (prefix_opt->flags & ND6_PREFIX_FLAG_AUTONOMOUS) {
/* Mark prefix as autonomous, so that address autoconfiguration can take place.
* Only OR flag, so that we don't over-write other flags (such as ADDRESS_DUPLICATE)*/
prefix_list[prefix].flags |= ND6_PREFIX_AUTOCONFIG_AUTONOMOUS;
}
#endif /* LWIP_IPV6_AUTOCONFIG */
}
}
break;
}
case ND6_OPTION_TYPE_ROUTE_INFO:
/* TODO implement preferred routes.
struct route_option * route_opt;
route_opt = (struct route_option *)buffer;*/
break;
default:
/* Unrecognized option, abort. */
ND6_STATS_INC(nd6.proterr);
break;
}
offset += 8 * ((u16_t)buffer[1]);
}
break; /* ICMP6_TYPE_RA */
}
case ICMP6_TYPE_RD: /* Redirect */
{
struct redirect_header * redir_hdr;
struct lladdr_option * lladdr_opt;
/* Check that Redir header fits in packet. */
if (p->len < sizeof(struct redirect_header)) {
/* TODO debug message */
pbuf_free(p);
ND6_STATS_INC(nd6.lenerr);
ND6_STATS_INC(nd6.drop);
return;
}
redir_hdr = (struct redirect_header *)p->payload;
if (p->len >= (sizeof(struct redirect_header) + 2)) {
lladdr_opt = (struct lladdr_option *)((u8_t*)p->payload + sizeof(struct redirect_header));
if (p->len < (sizeof(struct redirect_header) + (lladdr_opt->length << 3))) {
lladdr_opt = NULL;
}
} else {
lladdr_opt = NULL;
}
/* Copy original destination address to current source address, to have an aligned copy. */
ip6_addr_set(ip6_current_src_addr(), &(redir_hdr->destination_address));
/* Find dest address in cache */
i = nd6_find_destination_cache_entry(ip6_current_src_addr());
if (i < 0) {
/* Destination not in cache, drop packet. */
pbuf_free(p);
return;
}
/* Set the new target address. */
ip6_addr_set(&(destination_cache[i].next_hop_addr), &(redir_hdr->target_address));
/* If Link-layer address of other router is given, try to add to neighbor cache. */
if (lladdr_opt != NULL) {
if (lladdr_opt->type == ND6_OPTION_TYPE_TARGET_LLADDR) {
/* Copy target address to current source address, to have an aligned copy. */
ip6_addr_set(ip6_current_src_addr(), &(redir_hdr->target_address));
i = nd6_find_neighbor_cache_entry(ip6_current_src_addr());
if (i < 0) {
i = nd6_new_neighbor_cache_entry();
if (i >= 0) {
neighbor_cache[i].netif = inp;
MEMCPY(neighbor_cache[i].lladdr, lladdr_opt->addr, inp->hwaddr_len);
ip6_addr_set(&(neighbor_cache[i].next_hop_address), ip6_current_src_addr());
/* Receiving a message does not prove reachability: only in one direction.
* Delay probe in case we get confirmation of reachability from upper layer (TCP). */
neighbor_cache[i].state = ND6_DELAY;
neighbor_cache[i].counter.delay_time = LWIP_ND6_DELAY_FIRST_PROBE_TIME;
}
}
if (i >= 0) {
if (neighbor_cache[i].state == ND6_INCOMPLETE) {
MEMCPY(neighbor_cache[i].lladdr, lladdr_opt->addr, inp->hwaddr_len);
/* Receiving a message does not prove reachability: only in one direction.
* Delay probe in case we get confirmation of reachability from upper layer (TCP). */
neighbor_cache[i].state = ND6_DELAY;
neighbor_cache[i].counter.delay_time = LWIP_ND6_DELAY_FIRST_PROBE_TIME;
}
}
}
}
break; /* ICMP6_TYPE_RD */
}
case ICMP6_TYPE_PTB: /* Packet too big */
{
struct icmp6_hdr *icmp6hdr; /* Packet too big message */
struct ip6_hdr * ip6hdr; /* IPv6 header of the packet which caused the error */
u32_t pmtu;
/* Check that ICMPv6 header + IPv6 header fit in payload */
if (p->len < (sizeof(struct icmp6_hdr) + IP6_HLEN)) {
/* drop short packets */
pbuf_free(p);
ND6_STATS_INC(nd6.lenerr);
ND6_STATS_INC(nd6.drop);
return;
}
icmp6hdr = (struct icmp6_hdr *)p->payload;
ip6hdr = (struct ip6_hdr *)((u8_t*)p->payload + sizeof(struct icmp6_hdr));
/* Copy original destination address to current source address, to have an aligned copy. */
ip6_addr_set(ip6_current_src_addr(), &(ip6hdr->dest));
/* Look for entry in destination cache. */
i = nd6_find_destination_cache_entry(ip6_current_src_addr());
if (i < 0) {
/* Destination not in cache, drop packet. */
pbuf_free(p);
return;
}
/* Change the Path MTU. */
pmtu = htonl(icmp6hdr->data);
destination_cache[i].pmtu = (u16_t)LWIP_MIN(pmtu, 0xFFFF);
break; /* ICMP6_TYPE_PTB */
}
default:
ND6_STATS_INC(nd6.proterr);
ND6_STATS_INC(nd6.drop);
break; /* default */
}
pbuf_free(p);
}
/**
* Periodic timer for Neighbor discovery functions:
*
* - Update neighbor reachability states
* - Update destination cache entries age
* - Update invalidation timers of default routers and on-link prefixes
* - Perform duplicate address detection (DAD) for our addresses
* - Send router solicitations
*/
void
nd6_tmr(void)
{
s8_t i;
struct netif * netif;
/* Process neighbor entries. */
for (i = 0; i < LWIP_ND6_NUM_NEIGHBORS; i++) {
switch (neighbor_cache[i].state) {
case ND6_INCOMPLETE:
if ((neighbor_cache[i].counter.probes_sent >= LWIP_ND6_MAX_MULTICAST_SOLICIT) &&
(!neighbor_cache[i].isrouter)) {
/* Retries exceeded. */
nd6_free_neighbor_cache_entry(i);
} else {
/* Send a NS for this entry. */
neighbor_cache[i].counter.probes_sent++;
nd6_send_ns(neighbor_cache[i].netif, &(neighbor_cache[i].next_hop_address), ND6_SEND_FLAG_MULTICAST_DEST);
}
break;
case ND6_REACHABLE:
/* Send queued packets, if any are left. Should have been sent already. */
if (neighbor_cache[i].q != NULL) {
nd6_send_q(i);
}
if (neighbor_cache[i].counter.reachable_time <= ND6_TMR_INTERVAL) {
/* Change to stale state. */
neighbor_cache[i].state = ND6_STALE;
neighbor_cache[i].counter.stale_time = 0;
} else {
neighbor_cache[i].counter.reachable_time -= ND6_TMR_INTERVAL;
}
break;
case ND6_STALE:
neighbor_cache[i].counter.stale_time += ND6_TMR_INTERVAL;
break;
case ND6_DELAY:
if (neighbor_cache[i].counter.delay_time <= ND6_TMR_INTERVAL) {
/* Change to PROBE state. */
neighbor_cache[i].state = ND6_PROBE;
neighbor_cache[i].counter.probes_sent = 0;
} else {
neighbor_cache[i].counter.delay_time -= ND6_TMR_INTERVAL;
}
break;
case ND6_PROBE:
if ((neighbor_cache[i].counter.probes_sent >= LWIP_ND6_MAX_MULTICAST_SOLICIT) &&
(!neighbor_cache[i].isrouter)) {
/* Retries exceeded. */
nd6_free_neighbor_cache_entry(i);
} else {
/* Send a NS for this entry. */
neighbor_cache[i].counter.probes_sent++;
nd6_send_ns(neighbor_cache[i].netif, &(neighbor_cache[i].next_hop_address), 0);
}
break;
case ND6_NO_ENTRY:
default:
/* Do nothing. */
break;
}
}
/* Process destination entries. */
for (i = 0; i < LWIP_ND6_NUM_DESTINATIONS; i++) {
destination_cache[i].age++;
}
/* Process router entries. */
for (i = 0; i < LWIP_ND6_NUM_ROUTERS; i++) {
if (default_router_list[i].neighbor_entry != NULL) {
/* Active entry. */
if (default_router_list[i].invalidation_timer > 0) {
default_router_list[i].invalidation_timer -= ND6_TMR_INTERVAL / 1000;
}
if (default_router_list[i].invalidation_timer < ND6_TMR_INTERVAL / 1000) {
/* Less than 1 second remaining. Clear this entry. */
default_router_list[i].neighbor_entry->isrouter = 0;
default_router_list[i].neighbor_entry = NULL;
default_router_list[i].invalidation_timer = 0;
default_router_list[i].flags = 0;
}
}
}
/* Process prefix entries. */
for (i = 0; i < LWIP_ND6_NUM_PREFIXES; i++) {
if (prefix_list[i].netif != NULL) {
if (prefix_list[i].invalidation_timer < ND6_TMR_INTERVAL / 1000) {
/* Entry timed out, remove it */
prefix_list[i].invalidation_timer = 0;
#if LWIP_IPV6_AUTOCONFIG
/* If any addresses were configured with this prefix, remove them */
if (prefix_list[i].flags & ND6_PREFIX_AUTOCONFIG_ADDRESS_GENERATED)
{
s8_t j;
for (j = 1; j < LWIP_IPV6_NUM_ADDRESSES; j++) {
if ((netif_ip6_addr_state(prefix_list[i].netif, j) != IP6_ADDR_INVALID) &&
ip6_addr_netcmp(&prefix_list[i].prefix, netif_ip6_addr(prefix_list[i].netif, j))) {
netif_ip6_addr_set_state(prefix_list[i].netif, j, IP6_ADDR_INVALID);
prefix_list[i].flags = 0;
/* Exit loop. */
break;
}
}
}
#endif /* LWIP_IPV6_AUTOCONFIG */
prefix_list[i].netif = NULL;
prefix_list[i].flags = 0;
} else {
prefix_list[i].invalidation_timer -= ND6_TMR_INTERVAL / 1000;
#if LWIP_IPV6_AUTOCONFIG
/* Initiate address autoconfiguration for this prefix, if conditions are met. */
if (prefix_list[i].netif->ip6_autoconfig_enabled &&
(prefix_list[i].flags & ND6_PREFIX_AUTOCONFIG_AUTONOMOUS) &&
!(prefix_list[i].flags & ND6_PREFIX_AUTOCONFIG_ADDRESS_GENERATED)) {
s8_t j;
/* Try to get an address on this netif that is invalid.
* Skip 0 index (link-local address) */
for (j = 1; j < LWIP_IPV6_NUM_ADDRESSES; j++) {
if (netif_ip6_addr_state(prefix_list[i].netif, j) == IP6_ADDR_INVALID) {
/* Generate an address using this prefix and interface ID from link-local address. */
IP_ADDR6(&prefix_list[i].netif->ip6_addr[j],
prefix_list[i].prefix.addr[0], prefix_list[i].prefix.addr[1],
netif_ip6_addr(prefix_list[i].netif, 0)->addr[2], netif_ip6_addr(prefix_list[i].netif, 0)->addr[3]);
/* Mark it as tentative (DAD will be performed if configured). */
netif_ip6_addr_set_state(prefix_list[i].netif, j, IP6_ADDR_TENTATIVE);
/* Mark this prefix with ADDRESS_GENERATED, so that we don't try again. */
prefix_list[i].flags |= ND6_PREFIX_AUTOCONFIG_ADDRESS_GENERATED;
/* Exit loop. */
break;
}
}
}
#endif /* LWIP_IPV6_AUTOCONFIG */
}
}
}
/* Process our own addresses, if DAD configured. */
for (netif = netif_list; netif != NULL; netif = netif->next) {
for (i = 0; i < LWIP_IPV6_NUM_ADDRESSES; ++i) {
if (ip6_addr_istentative(netif->ip6_addr_state[i])) {
if ((netif->ip6_addr_state[i] & 0x07) >= LWIP_IPV6_DUP_DETECT_ATTEMPTS) {
/* No NA received in response. Mark address as valid. */
netif->ip6_addr_state[i] = IP6_ADDR_PREFERRED;
/* TODO implement preferred and valid lifetimes. */
} else if (netif->flags & NETIF_FLAG_UP) {
#if LWIP_IPV6_MLD
if ((netif->ip6_addr_state[i] & 0x07) == 0) {
/* Join solicited node multicast group. */
ip6_addr_set_solicitednode(&multicast_address, netif_ip6_addr(netif, i)->addr[3]);
mld6_joingroup(netif_ip6_addr(netif, i), &multicast_address);
}
#endif /* LWIP_IPV6_MLD */
/* Send a NS for this address. */
nd6_send_ns(netif, netif_ip6_addr(netif, i), ND6_SEND_FLAG_MULTICAST_DEST);
(netif->ip6_addr_state[i])++;
/* TODO send max 1 NS per tmr call? enable return*/
/*return;*/
}
}
}
}
#if LWIP_IPV6_SEND_ROUTER_SOLICIT
/* Send router solicitation messages, if necessary. */
for (netif = netif_list; netif != NULL; netif = netif->next) {
if ((netif->rs_count > 0) && (netif->flags & NETIF_FLAG_UP) &&
(!ip6_addr_isinvalid(netif_ip6_addr_state(netif, 0)))) {
if (nd6_send_rs(netif) == ERR_OK) {
netif->rs_count--;
}
}
}
#endif /* LWIP_IPV6_SEND_ROUTER_SOLICIT */
}
/**
* Send a neighbor solicitation message
*
* @param netif the netif on which to send the message
* @param target_addr the IPv6 target address for the ND message
* @param flags one of ND6_SEND_FLAG_*
*/
static void
nd6_send_ns(struct netif * netif, const ip6_addr_t * target_addr, u8_t flags)
{
struct ns_header * ns_hdr;
struct lladdr_option * lladdr_opt;
struct pbuf * p;
const ip6_addr_t * src_addr;
u16_t lladdr_opt_len;
if (ip6_addr_isvalid(netif_ip6_addr_state(netif,0))) {
/* Use link-local address as source address. */
src_addr = netif_ip6_addr(netif, 0);
} else {
src_addr = IP6_ADDR_ANY6;
}
/* Allocate a packet. */
lladdr_opt_len = ((netif->hwaddr_len + 2) >> 3) + (((netif->hwaddr_len + 2) & 0x07) ? 1 : 0);
p = pbuf_alloc(PBUF_IP, sizeof(struct ns_header) + (lladdr_opt_len << 3), PBUF_RAM);
if (p == NULL) {
ND6_STATS_INC(nd6.memerr);
return;
}
/* Set fields. */
ns_hdr = (struct ns_header *)p->payload;
lladdr_opt = (struct lladdr_option *)((u8_t*)p->payload + sizeof(struct ns_header));
ns_hdr->type = ICMP6_TYPE_NS;
ns_hdr->code = 0;
ns_hdr->chksum = 0;
ns_hdr->reserved = 0;
ip6_addr_set(&(ns_hdr->target_address), target_addr);
lladdr_opt->type = ND6_OPTION_TYPE_SOURCE_LLADDR;
lladdr_opt->length = (u8_t)lladdr_opt_len;
SMEMCPY(lladdr_opt->addr, netif->hwaddr, netif->hwaddr_len);
/* Generate the solicited node address for the target address. */
if (flags & ND6_SEND_FLAG_MULTICAST_DEST) {
ip6_addr_set_solicitednode(&multicast_address, target_addr->addr[3]);
target_addr = &multicast_address;
}
#if CHECKSUM_GEN_ICMP6
IF__NETIF_CHECKSUM_ENABLED(netif, NETIF_CHECKSUM_GEN_ICMP6) {
ns_hdr->chksum = ip6_chksum_pseudo(p, IP6_NEXTH_ICMP6, p->len, src_addr,
target_addr);
}
#endif /* CHECKSUM_GEN_ICMP6 */
/* Send the packet out. */
ND6_STATS_INC(nd6.xmit);
ip6_output_if(p, (src_addr == IP6_ADDR_ANY6) ? NULL : src_addr, target_addr,
LWIP_ICMP6_HL, 0, IP6_NEXTH_ICMP6, netif);
pbuf_free(p);
}
/**
* Send a neighbor advertisement message
*
* @param netif the netif on which to send the message
* @param target_addr the IPv6 target address for the ND message
* @param flags one of ND6_SEND_FLAG_*
*/
static void
nd6_send_na(struct netif * netif, const ip6_addr_t * target_addr, u8_t flags)
{
struct na_header * na_hdr;
struct lladdr_option * lladdr_opt;
struct pbuf * p;
const ip6_addr_t * src_addr;
const ip6_addr_t * dest_addr;
u16_t lladdr_opt_len;
/* Use link-local address as source address. */
/* src_addr = &(netif->ip6_addr[0]); */
/* Use target address as source address. */
src_addr = target_addr;
/* Allocate a packet. */
lladdr_opt_len = ((netif->hwaddr_len + 2) >> 3) + (((netif->hwaddr_len + 2) & 0x07) ? 1 : 0);
p = pbuf_alloc(PBUF_IP, sizeof(struct na_header) + (lladdr_opt_len << 3), PBUF_RAM);
if (p == NULL) {
ND6_STATS_INC(nd6.memerr);
return;
}
/* Set fields. */
na_hdr = (struct na_header *)p->payload;
lladdr_opt = (struct lladdr_option *)((u8_t*)p->payload + sizeof(struct na_header));
na_hdr->type = ICMP6_TYPE_NA;
na_hdr->code = 0;
na_hdr->chksum = 0;
na_hdr->flags = flags & 0xf0;
na_hdr->reserved[0] = 0;
na_hdr->reserved[1] = 0;
na_hdr->reserved[2] = 0;
ip6_addr_set(&(na_hdr->target_address), target_addr);
lladdr_opt->type = ND6_OPTION_TYPE_TARGET_LLADDR;
lladdr_opt->length = (u8_t)lladdr_opt_len;
SMEMCPY(lladdr_opt->addr, netif->hwaddr, netif->hwaddr_len);
/* Generate the solicited node address for the target address. */
if (flags & ND6_SEND_FLAG_MULTICAST_DEST) {
ip6_addr_set_solicitednode(&multicast_address, target_addr->addr[3]);
dest_addr = &multicast_address;
} else if (flags & ND6_SEND_FLAG_ALLNODES_DEST) {
ip6_addr_set_allnodes_linklocal(&multicast_address);
dest_addr = &multicast_address;
} else {
dest_addr = ip6_current_src_addr();
}
#if CHECKSUM_GEN_ICMP6
IF__NETIF_CHECKSUM_ENABLED(netif, NETIF_CHECKSUM_GEN_ICMP6) {
na_hdr->chksum = ip6_chksum_pseudo(p, IP6_NEXTH_ICMP6, p->len, src_addr,
dest_addr);
}
#endif /* CHECKSUM_GEN_ICMP6 */
/* Send the packet out. */
ND6_STATS_INC(nd6.xmit);
ip6_output_if(p, src_addr, dest_addr,
LWIP_ICMP6_HL, 0, IP6_NEXTH_ICMP6, netif);
pbuf_free(p);
}
#if LWIP_IPV6_SEND_ROUTER_SOLICIT
/**
* Send a router solicitation message
*
* @param netif the netif on which to send the message
*/
static err_t
nd6_send_rs(struct netif * netif)
{
struct rs_header * rs_hdr;
struct lladdr_option * lladdr_opt;
struct pbuf * p;
const ip6_addr_t * src_addr;
err_t err;
u16_t lladdr_opt_len = 0;
/* Link-local source address, or unspecified address? */
if (ip6_addr_isvalid(netif_ip6_addr_state(netif, 0))) {
src_addr = netif_ip6_addr(netif, 0);
} else {
src_addr = IP6_ADDR_ANY6;
}
/* Generate the all routers target address. */
ip6_addr_set_allrouters_linklocal(&multicast_address);
/* Allocate a packet. */
if (src_addr != IP6_ADDR_ANY6) {
lladdr_opt_len = ((netif->hwaddr_len + 2) >> 3) + (((netif->hwaddr_len + 2) & 0x07) ? 1 : 0);
}
p = pbuf_alloc(PBUF_IP, sizeof(struct rs_header) + (lladdr_opt_len << 3), PBUF_RAM);
if (p == NULL) {
ND6_STATS_INC(nd6.memerr);
return ERR_BUF;
}
/* Set fields. */
rs_hdr = (struct rs_header *)p->payload;
rs_hdr->type = ICMP6_TYPE_RS;
rs_hdr->code = 0;
rs_hdr->chksum = 0;
rs_hdr->reserved = 0;
if (src_addr != IP6_ADDR_ANY6) {
/* Include our hw address. */
lladdr_opt = (struct lladdr_option *)((u8_t*)p->payload + sizeof(struct rs_header));
lladdr_opt->type = ND6_OPTION_TYPE_SOURCE_LLADDR;
lladdr_opt->length = (u8_t)lladdr_opt_len;
SMEMCPY(lladdr_opt->addr, netif->hwaddr, netif->hwaddr_len);
}
#if CHECKSUM_GEN_ICMP6
IF__NETIF_CHECKSUM_ENABLED(netif, NETIF_CHECKSUM_GEN_ICMP6) {
rs_hdr->chksum = ip6_chksum_pseudo(p, IP6_NEXTH_ICMP6, p->len, src_addr,
&multicast_address);
}
#endif /* CHECKSUM_GEN_ICMP6 */
/* Send the packet out. */
ND6_STATS_INC(nd6.xmit);
err = ip6_output_if(p, (src_addr == IP6_ADDR_ANY6) ? NULL : src_addr, &multicast_address,
LWIP_ICMP6_HL, 0, IP6_NEXTH_ICMP6, netif);
pbuf_free(p);
return err;
}
#endif /* LWIP_IPV6_SEND_ROUTER_SOLICIT */
/**
* Search for a neighbor cache entry
*
* @param ip6addr the IPv6 address of the neighbor
* @return The neighbor cache entry index that matched, -1 if no
* entry is found
*/
static s8_t
nd6_find_neighbor_cache_entry(const ip6_addr_t * ip6addr)
{
s8_t i;
for (i = 0; i < LWIP_ND6_NUM_NEIGHBORS; i++) {
if (ip6_addr_cmp(ip6addr, &(neighbor_cache[i].next_hop_address))) {
return i;
}
}
return -1;
}
/**
* Create a new neighbor cache entry.
*
* If no unused entry is found, will try to recycle an old entry
* according to ad-hoc "age" heuristic.
*
* @return The neighbor cache entry index that was created, -1 if no
* entry could be created
*/
static s8_t
nd6_new_neighbor_cache_entry(void)
{
s8_t i;
s8_t j;
u32_t time;
/* First, try to find an empty entry. */
for (i = 0; i < LWIP_ND6_NUM_NEIGHBORS; i++) {
if (neighbor_cache[i].state == ND6_NO_ENTRY) {
return i;
}
}
/* We need to recycle an entry. in general, do not recycle if it is a router. */
/* Next, try to find a Stale entry. */
for (i = 0; i < LWIP_ND6_NUM_NEIGHBORS; i++) {
if ((neighbor_cache[i].state == ND6_STALE) &&
(!neighbor_cache[i].isrouter)) {
nd6_free_neighbor_cache_entry(i);
return i;
}
}
/* Next, try to find a Probe entry. */
for (i = 0; i < LWIP_ND6_NUM_NEIGHBORS; i++) {
if ((neighbor_cache[i].state == ND6_PROBE) &&
(!neighbor_cache[i].isrouter)) {
nd6_free_neighbor_cache_entry(i);
return i;
}
}
/* Next, try to find a Delayed entry. */
for (i = 0; i < LWIP_ND6_NUM_NEIGHBORS; i++) {
if ((neighbor_cache[i].state == ND6_DELAY) &&
(!neighbor_cache[i].isrouter)) {
nd6_free_neighbor_cache_entry(i);
return i;
}
}
/* Next, try to find the oldest reachable entry. */
time = 0xfffffffful;
j = -1;
for (i = 0; i < LWIP_ND6_NUM_NEIGHBORS; i++) {
if ((neighbor_cache[i].state == ND6_REACHABLE) &&
(!neighbor_cache[i].isrouter)) {
if (neighbor_cache[i].counter.reachable_time < time) {
j = i;
time = neighbor_cache[i].counter.reachable_time;
}
}
}
if (j >= 0) {
nd6_free_neighbor_cache_entry(j);
return j;
}
/* Next, find oldest incomplete entry without queued packets. */
time = 0;
j = -1;
for (i = 0; i < LWIP_ND6_NUM_NEIGHBORS; i++) {
if (
(neighbor_cache[i].q == NULL) &&
(neighbor_cache[i].state == ND6_INCOMPLETE) &&
(!neighbor_cache[i].isrouter)) {
if (neighbor_cache[i].counter.probes_sent >= time) {
j = i;
time = neighbor_cache[i].counter.probes_sent;
}
}
}
if (j >= 0) {
nd6_free_neighbor_cache_entry(j);
return j;
}
/* Next, find oldest incomplete entry with queued packets. */
time = 0;
j = -1;
for (i = 0; i < LWIP_ND6_NUM_NEIGHBORS; i++) {
if ((neighbor_cache[i].state == ND6_INCOMPLETE) &&
(!neighbor_cache[i].isrouter)) {
if (neighbor_cache[i].counter.probes_sent >= time) {
j = i;
time = neighbor_cache[i].counter.probes_sent;
}
}
}
if (j >= 0) {
nd6_free_neighbor_cache_entry(j);
return j;
}
/* No more entries to try. */
return -1;
}
/**
* Will free any resources associated with a neighbor cache
* entry, and will mark it as unused.
*
* @param i the neighbor cache entry index to free
*/
static void
nd6_free_neighbor_cache_entry(s8_t i)
{
if ((i < 0) || (i >= LWIP_ND6_NUM_NEIGHBORS)) {
return;
}
if (neighbor_cache[i].isrouter) {
/* isrouter needs to be cleared before deleting a neighbor cache entry */
return;
}
/* Free any queued packets. */
if (neighbor_cache[i].q != NULL) {
nd6_free_q(neighbor_cache[i].q);
neighbor_cache[i].q = NULL;
}
neighbor_cache[i].state = ND6_NO_ENTRY;
neighbor_cache[i].isrouter = 0;
neighbor_cache[i].netif = NULL;
neighbor_cache[i].counter.reachable_time = 0;
ip6_addr_set_zero(&(neighbor_cache[i].next_hop_address));
}
/**
* Search for a destination cache entry
*
* @param ip6addr the IPv6 address of the destination
* @return The destination cache entry index that matched, -1 if no
* entry is found
*/
static s8_t
nd6_find_destination_cache_entry(const ip6_addr_t * ip6addr)
{
s8_t i;
for (i = 0; i < LWIP_ND6_NUM_DESTINATIONS; i++) {
if (ip6_addr_cmp(ip6addr, &(destination_cache[i].destination_addr))) {
return i;
}
}
return -1;
}
/**
* Create a new destination cache entry. If no unused entry is found,
* will recycle oldest entry.
*
* @return The destination cache entry index that was created, -1 if no
* entry was created
*/
static s8_t
nd6_new_destination_cache_entry(void)
{
s8_t i, j;
u32_t age;
/* Find an empty entry. */
for (i = 0; i < LWIP_ND6_NUM_DESTINATIONS; i++) {
if (ip6_addr_isany(&(destination_cache[i].destination_addr))) {
return i;
}
}
/* Find oldest entry. */
age = 0;
j = LWIP_ND6_NUM_DESTINATIONS - 1;
for (i = 0; i < LWIP_ND6_NUM_DESTINATIONS; i++) {
if (destination_cache[i].age > age) {
j = i;
}
}
return j;
}
/**
* Determine whether an address matches an on-link prefix.
*
* @param ip6addr the IPv6 address to match
* @return 1 if the address is on-link, 0 otherwise
*/
static s8_t
nd6_is_prefix_in_netif(const ip6_addr_t * ip6addr, struct netif * netif)
{
s8_t i;
for (i = 0; i < LWIP_ND6_NUM_PREFIXES; i++) {
if ((prefix_list[i].netif == netif) &&
(prefix_list[i].invalidation_timer > 0) &&
ip6_addr_netcmp(ip6addr, &(prefix_list[i].prefix))) {
return 1;
}
}
/* Check to see if address prefix matches a (manually?) configured address. */
for (i = 0; i < LWIP_IPV6_NUM_ADDRESSES; i++) {
if (ip6_addr_isvalid(netif_ip6_addr_state(netif, i)) &&
ip6_addr_netcmp(ip6addr, netif_ip6_addr(netif, i))) {
return 1;
}
}
return 0;
}
/**
* Select a default router for a destination.
*
* @param ip6addr the destination address
* @param netif the netif for the outgoing packet, if known
* @return the default router entry index, or -1 if no suitable
* router is found
*/
s8_t
nd6_select_router(const ip6_addr_t * ip6addr, struct netif * netif)
{
s8_t i;
/* last_router is used for round-robin router selection (as recommended
* in RFC). This is more robust in case one router is not reachable,
* we are not stuck trying to resolve it. */
static s8_t last_router;
(void)ip6addr; /* TODO match preferred routes!! (must implement ND6_OPTION_TYPE_ROUTE_INFO) */
/* TODO: implement default router preference */
/* Look for reachable routers. */
for (i = 0; i < LWIP_ND6_NUM_ROUTERS; i++) {
if (++last_router >= LWIP_ND6_NUM_ROUTERS) {
last_router = 0;
}
if ((default_router_list[i].neighbor_entry != NULL) &&
(netif != NULL ? netif == default_router_list[i].neighbor_entry->netif : 1) &&
(default_router_list[i].invalidation_timer > 0) &&
(default_router_list[i].neighbor_entry->state == ND6_REACHABLE)) {
return i;
}
}
/* Look for router in other reachability states, but still valid according to timer. */
for (i = 0; i < LWIP_ND6_NUM_ROUTERS; i++) {
if (++last_router >= LWIP_ND6_NUM_ROUTERS) {
last_router = 0;
}
if ((default_router_list[i].neighbor_entry != NULL) &&
(netif != NULL ? netif == default_router_list[i].neighbor_entry->netif : 1) &&
(default_router_list[i].invalidation_timer > 0)) {
return i;
}
}
/* Look for any router for which we have any information at all. */
for (i = 0; i < LWIP_ND6_NUM_ROUTERS; i++) {
if (++last_router >= LWIP_ND6_NUM_ROUTERS) {
last_router = 0;
}
if (default_router_list[i].neighbor_entry != NULL &&
(netif != NULL ? netif == default_router_list[i].neighbor_entry->netif : 1)) {
return i;
}
}
/* no suitable router found. */
return -1;
}
/**
* Find an entry for a default router.
*
* @param router_addr the IPv6 address of the router
* @param netif the netif on which the router is found, if known
* @return the index of the router entry, or -1 if not found
*/
static s8_t
nd6_get_router(const ip6_addr_t * router_addr, struct netif * netif)
{
s8_t i;
/* Look for router. */
for (i = 0; i < LWIP_ND6_NUM_ROUTERS; i++) {
if ((default_router_list[i].neighbor_entry != NULL) &&
((netif != NULL) ? netif == default_router_list[i].neighbor_entry->netif : 1) &&
ip6_addr_cmp(router_addr, &(default_router_list[i].neighbor_entry->next_hop_address))) {
return i;
}
}
/* router not found. */
return -1;
}
/**
* Create a new entry for a default router.
*
* @param router_addr the IPv6 address of the router
* @param netif the netif on which the router is connected, if known
* @return the index on the router table, or -1 if could not be created
*/
static s8_t
nd6_new_router(const ip6_addr_t * router_addr, struct netif * netif)
{
s8_t router_index;
s8_t neighbor_index;
/* Do we have a neighbor entry for this router? */
neighbor_index = nd6_find_neighbor_cache_entry(router_addr);
if (neighbor_index < 0) {
/* Create a neighbor entry for this router. */
neighbor_index = nd6_new_neighbor_cache_entry();
if (neighbor_index < 0) {
/* Could not create neighbor entry for this router. */
return -1;
}
ip6_addr_set(&(neighbor_cache[neighbor_index].next_hop_address), router_addr);
neighbor_cache[neighbor_index].netif = netif;
neighbor_cache[neighbor_index].q = NULL;
neighbor_cache[neighbor_index].state = ND6_INCOMPLETE;
neighbor_cache[neighbor_index].counter.probes_sent = 0;
}
/* Mark neighbor as router. */
neighbor_cache[neighbor_index].isrouter = 1;
/* Look for empty entry. */
for (router_index = 0; router_index < LWIP_ND6_NUM_ROUTERS; router_index++) {
if (default_router_list[router_index].neighbor_entry == NULL) {
default_router_list[router_index].neighbor_entry = &(neighbor_cache[neighbor_index]);
return router_index;
}
}
/* Could not create a router entry. */
/* Mark neighbor entry as not-router. Entry might be useful as neighbor still. */
neighbor_cache[neighbor_index].isrouter = 0;
/* router not found. */
return -1;
}
/**
* Find the cached entry for an on-link prefix.
*
* @param prefix the IPv6 prefix that is on-link
* @param netif the netif on which the prefix is on-link
* @return the index on the prefix table, or -1 if not found
*/
static s8_t
nd6_get_onlink_prefix(ip6_addr_t * prefix, struct netif * netif)
{
s8_t i;
/* Look for prefix in list. */
for (i = 0; i < LWIP_ND6_NUM_PREFIXES; ++i) {
if ((ip6_addr_netcmp(&(prefix_list[i].prefix), prefix)) &&
(prefix_list[i].netif == netif)) {
return i;
}
}
/* Entry not available. */
return -1;
}
/**
* Creates a new entry for an on-link prefix.
*
* @param prefix the IPv6 prefix that is on-link
* @param netif the netif on which the prefix is on-link
* @return the index on the prefix table, or -1 if not created
*/
static s8_t
nd6_new_onlink_prefix(ip6_addr_t * prefix, struct netif * netif)
{
s8_t i;
/* Create new entry. */
for (i = 0; i < LWIP_ND6_NUM_PREFIXES; ++i) {
if ((prefix_list[i].netif == NULL) ||
(prefix_list[i].invalidation_timer == 0)) {
/* Found empty prefix entry. */
prefix_list[i].netif = netif;
ip6_addr_set(&(prefix_list[i].prefix), prefix);
#if LWIP_IPV6_AUTOCONFIG
prefix_list[i].flags = 0;
#endif /* LWIP_IPV6_AUTOCONFIG */
return i;
}
}
/* Entry not available. */
return -1;
}
/**
* Determine the next hop for a destination. Will determine if the
* destination is on-link, else a suitable on-link router is selected.
*
* The last entry index is cached for fast entry search.
*
* @param ip6addr the destination address
* @param netif the netif on which the packet will be sent
* @return the neighbor cache entry for the next hop, ERR_RTE if no
* suitable next hop was found, ERR_MEM if no cache entry
* could be created
*/
s8_t
nd6_get_next_hop_entry(const ip6_addr_t * ip6addr, struct netif * netif)
{
s8_t i;
#if LWIP_NETIF_HWADDRHINT
if (netif->addr_hint != NULL) {
/* per-pcb cached entry was given */
u8_t addr_hint = *(netif->addr_hint);
if (addr_hint < LWIP_ND6_NUM_DESTINATIONS) {
nd6_cached_destination_index = addr_hint;
}
}
#endif /* LWIP_NETIF_HWADDRHINT */
/* Look for ip6addr in destination cache. */
if (ip6_addr_cmp(ip6addr, &(destination_cache[nd6_cached_destination_index].destination_addr))) {
/* the cached entry index is the right one! */
/* do nothing. */
ND6_STATS_INC(nd6.cachehit);
} else {
/* Search destination cache. */
i = nd6_find_destination_cache_entry(ip6addr);
if (i >= 0) {
/* found destination entry. make it our new cached index. */
nd6_cached_destination_index = i;
} else {
/* Not found. Create a new destination entry. */
i = nd6_new_destination_cache_entry();
if (i >= 0) {
/* got new destination entry. make it our new cached index. */
nd6_cached_destination_index = i;
} else {
/* Could not create a destination cache entry. */
return ERR_MEM;
}
/* Copy dest address to destination cache. */
ip6_addr_set(&(destination_cache[nd6_cached_destination_index].destination_addr), ip6addr);
/* Now find the next hop. is it a neighbor? */
if (ip6_addr_islinklocal(ip6addr) ||
nd6_is_prefix_in_netif(ip6addr, netif)) {
/* Destination in local link. */
destination_cache[nd6_cached_destination_index].pmtu = netif->mtu;
ip6_addr_copy(destination_cache[nd6_cached_destination_index].next_hop_addr, destination_cache[nd6_cached_destination_index].destination_addr);
} else {
/* We need to select a router. */
i = nd6_select_router(ip6addr, netif);
if (i < 0) {
/* No router found. */
ip6_addr_set_any(&(destination_cache[nd6_cached_destination_index].destination_addr));
return ERR_RTE;
}
destination_cache[nd6_cached_destination_index].pmtu = netif->mtu; /* Start with netif mtu, correct through ICMPv6 if necessary */
ip6_addr_copy(destination_cache[nd6_cached_destination_index].next_hop_addr, default_router_list[i].neighbor_entry->next_hop_address);
}
}
}
#if LWIP_NETIF_HWADDRHINT
if (netif->addr_hint != NULL) {
/* per-pcb cached entry was given */
*(netif->addr_hint) = nd6_cached_destination_index;
}
#endif /* LWIP_NETIF_HWADDRHINT */
/* Look in neighbor cache for the next-hop address. */
if (ip6_addr_cmp(&(destination_cache[nd6_cached_destination_index].next_hop_addr),
&(neighbor_cache[nd6_cached_neighbor_index].next_hop_address))) {
/* Cache hit. */
/* Do nothing. */
ND6_STATS_INC(nd6.cachehit);
} else {
i = nd6_find_neighbor_cache_entry(&(destination_cache[nd6_cached_destination_index].next_hop_addr));
if (i >= 0) {
/* Found a matching record, make it new cached entry. */
nd6_cached_neighbor_index = i;
} else {
/* Neighbor not in cache. Make a new entry. */
i = nd6_new_neighbor_cache_entry();
if (i >= 0) {
/* got new neighbor entry. make it our new cached index. */
nd6_cached_neighbor_index = i;
} else {
/* Could not create a neighbor cache entry. */
return ERR_MEM;
}
/* Initialize fields. */
ip6_addr_copy(neighbor_cache[i].next_hop_address,
destination_cache[nd6_cached_destination_index].next_hop_addr);
neighbor_cache[i].isrouter = 0;
neighbor_cache[i].netif = netif;
neighbor_cache[i].state = ND6_INCOMPLETE;
neighbor_cache[i].counter.probes_sent = 0;
}
}
/* Reset this destination's age. */
destination_cache[nd6_cached_destination_index].age = 0;
return nd6_cached_neighbor_index;
}
/**
* Queue a packet for a neighbor.
*
* @param neighbor_index the index in the neighbor cache table
* @param q packet to be queued
* @return ERR_OK if succeeded, ERR_MEM if out of memory
*/
err_t
nd6_queue_packet(s8_t neighbor_index, struct pbuf * q)
{
err_t result = ERR_MEM;
struct pbuf *p;
int copy_needed = 0;
#if LWIP_ND6_QUEUEING
struct nd6_q_entry *new_entry, *r;
#endif /* LWIP_ND6_QUEUEING */
if ((neighbor_index < 0) || (neighbor_index >= LWIP_ND6_NUM_NEIGHBORS)) {
return ERR_ARG;
}
/* IF q includes a PBUF_REF, PBUF_POOL or PBUF_RAM, we have no choice but
* to copy the whole queue into a new PBUF_RAM (see bug #11400)
* PBUF_ROMs can be left as they are, since ROM must not get changed. */
p = q;
while (p) {
if (p->type != PBUF_ROM) {
copy_needed = 1;
break;
}
p = p->next;
}
if (copy_needed) {
/* copy the whole packet into new pbufs */
p = pbuf_alloc(PBUF_LINK, q->tot_len, PBUF_RAM);
while ((p == NULL) && (neighbor_cache[neighbor_index].q != NULL)) {
/* Free oldest packet (as per RFC recommendation) */
#if LWIP_ND6_QUEUEING
r = neighbor_cache[neighbor_index].q;
neighbor_cache[neighbor_index].q = r->next;
r->next = NULL;
nd6_free_q(r);
#else /* LWIP_ND6_QUEUEING */
pbuf_free(neighbor_cache[neighbor_index].q);
neighbor_cache[neighbor_index].q = NULL;
#endif /* LWIP_ND6_QUEUEING */
p = pbuf_alloc(PBUF_LINK, q->tot_len, PBUF_RAM);
}
if (p != NULL) {
if (pbuf_copy(p, q) != ERR_OK) {
pbuf_free(p);
p = NULL;
}
}
} else {
/* referencing the old pbuf is enough */
p = q;
pbuf_ref(p);
}
/* packet was copied/ref'd? */
if (p != NULL) {
/* queue packet ... */
#if LWIP_ND6_QUEUEING
/* allocate a new nd6 queue entry */
new_entry = (struct nd6_q_entry *)memp_malloc(MEMP_ND6_QUEUE);
if ((new_entry == NULL) && (neighbor_cache[neighbor_index].q != NULL)) {
/* Free oldest packet (as per RFC recommendation) */
r = neighbor_cache[neighbor_index].q;
neighbor_cache[neighbor_index].q = r->next;
r->next = NULL;
nd6_free_q(r);
new_entry = (struct nd6_q_entry *)memp_malloc(MEMP_ND6_QUEUE);
}
if (new_entry != NULL) {
new_entry->next = NULL;
new_entry->p = p;
if (neighbor_cache[neighbor_index].q != NULL) {
/* queue was already existent, append the new entry to the end */
r = neighbor_cache[neighbor_index].q;
while (r->next != NULL) {
r = r->next;
}
r->next = new_entry;
} else {
/* queue did not exist, first item in queue */
neighbor_cache[neighbor_index].q = new_entry;
}
LWIP_DEBUGF(LWIP_DBG_TRACE, ("ipv6: queued packet %p on neighbor entry %"S16_F"\n", (void *)p, (s16_t)neighbor_index));
result = ERR_OK;
} else {
/* the pool MEMP_ND6_QUEUE is empty */
pbuf_free(p);
LWIP_DEBUGF(LWIP_DBG_TRACE, ("ipv6: could not queue a copy of packet %p (out of memory)\n", (void *)p));
/* { result == ERR_MEM } through initialization */
}
#else /* LWIP_ND6_QUEUEING */
/* Queue a single packet. If an older packet is already queued, free it as per RFC. */
if (neighbor_cache[neighbor_index].q != NULL) {
pbuf_free(neighbor_cache[neighbor_index].q);
}
neighbor_cache[neighbor_index].q = p;
LWIP_DEBUGF(LWIP_DBG_TRACE, ("ipv6: queued packet %p on neighbor entry %"S16_F"\n", (void *)p, (s16_t)neighbor_index));
result = ERR_OK;
#endif /* LWIP_ND6_QUEUEING */
} else {
LWIP_DEBUGF(LWIP_DBG_TRACE, ("ipv6: could not queue a copy of packet %p (out of memory)\n", (void *)q));
/* { result == ERR_MEM } through initialization */
}
return result;
}
#if LWIP_ND6_QUEUEING
/**
* Free a complete queue of nd6 q entries
*
* @param q a queue of nd6_q_entry to free
*/
static void
nd6_free_q(struct nd6_q_entry *q)
{
struct nd6_q_entry *r;
LWIP_ASSERT("q != NULL", q != NULL);
LWIP_ASSERT("q->p != NULL", q->p != NULL);
while (q) {
r = q;
q = q->next;
LWIP_ASSERT("r->p != NULL", (r->p != NULL));
pbuf_free(r->p);
memp_free(MEMP_ND6_QUEUE, r);
}
}
#endif /* LWIP_ND6_QUEUEING */
/**
* Send queued packets for a neighbor
*
* @param i the neighbor to send packets to
*/
static void
nd6_send_q(s8_t i)
{
struct ip6_hdr *ip6hdr;
#if LWIP_ND6_QUEUEING
struct nd6_q_entry *q;
#endif /* LWIP_ND6_QUEUEING */
if ((i < 0) || (i >= LWIP_ND6_NUM_NEIGHBORS)) {
return;
}
#if LWIP_ND6_QUEUEING
while (neighbor_cache[i].q != NULL) {
/* remember first in queue */
q = neighbor_cache[i].q;
/* pop first item off the queue */
neighbor_cache[i].q = q->next;
/* Get ipv6 header. */
ip6hdr = (struct ip6_hdr *)(q->p->payload);
/* Override ip6_current_dest_addr() so that we have an aligned copy. */
ip6_addr_set(ip6_current_dest_addr(), &(ip6hdr->dest));
/* send the queued IPv6 packet */
(neighbor_cache[i].netif)->output_ip6(neighbor_cache[i].netif, q->p, ip6_current_dest_addr());
/* free the queued IP packet */
pbuf_free(q->p);
/* now queue entry can be freed */
memp_free(MEMP_ND6_QUEUE, q);
}
#else /* LWIP_ND6_QUEUEING */
if (neighbor_cache[i].q != NULL) {
/* Get ipv6 header. */
ip6hdr = (struct ip6_hdr *)(neighbor_cache[i].q->payload);
/* Override ip6_current_dest_addr() so that we have an aligned copy. */
ip6_addr_set(ip6_current_dest_addr(), &(ip6hdr->dest));
/* send the queued IPv6 packet */
(neighbor_cache[i].netif)->output_ip6(neighbor_cache[i].netif, neighbor_cache[i].q, ip6_current_dest_addr());
/* free the queued IP packet */
pbuf_free(neighbor_cache[i].q);
neighbor_cache[i].q = NULL;
}
#endif /* LWIP_ND6_QUEUEING */
}
/**
* Get the Path MTU for a destination.
*
* @param ip6addr the destination address
* @param netif the netif on which the packet will be sent
* @return the Path MTU, if known, or the netif default MTU
*/
u16_t
nd6_get_destination_mtu(const ip6_addr_t * ip6addr, struct netif * netif)
{
s8_t i;
i = nd6_find_destination_cache_entry(ip6addr);
if (i >= 0) {
if (destination_cache[i].pmtu > 0) {
return destination_cache[i].pmtu;
}
}
if (netif != NULL) {
return netif->mtu;
}
return 1280; /* Minimum MTU */
}
#if LWIP_ND6_TCP_REACHABILITY_HINTS
/**
* Provide the Neighbor discovery process with a hint that a
* destination is reachable. Called by tcp_receive when ACKs are
* received or sent (as per RFC). This is useful to avoid sending
* NS messages every 30 seconds.
*
* @param ip6addr the destination address which is know to be reachable
* by an upper layer protocol (TCP)
*/
void
nd6_reachability_hint(const ip6_addr_t * ip6addr)
{
s8_t i;
/* Find destination in cache. */
if (ip6_addr_cmp(ip6addr, &(destination_cache[nd6_cached_destination_index].destination_addr))) {
i = nd6_cached_destination_index;
ND6_STATS_INC(nd6.cachehit);
} else {
i = nd6_find_destination_cache_entry(ip6addr);
}
if (i < 0) {
return;
}
/* Find next hop neighbor in cache. */
if (ip6_addr_cmp(&(destination_cache[i].next_hop_addr), &(neighbor_cache[nd6_cached_neighbor_index].next_hop_address))) {
i = nd6_cached_neighbor_index;
ND6_STATS_INC(nd6.cachehit);
} else {
i = nd6_find_neighbor_cache_entry(&(destination_cache[i].next_hop_addr));
}
if (i < 0) {
return;
}
/* For safety: don't set as reachable if we don't have a LL address yet. Misuse protection. */
if (neighbor_cache[i].state == ND6_INCOMPLETE || neighbor_cache[i].state == ND6_NO_ENTRY) {
return;
}
/* Set reachability state. */
neighbor_cache[i].state = ND6_REACHABLE;
neighbor_cache[i].counter.reachable_time = reachable_time;
}
#endif /* LWIP_ND6_TCP_REACHABILITY_HINTS */
#endif /* LWIP_IPV6 */
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