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pigweed / third_party / github / STMicroelectronics / stm32_mw_lwip / refs/heads/main / . / src / core / ipv6 / nd6.c
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/**
* @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/priv/nd6_priv.h"
#include "lwip/prot/nd6.h"
#include "lwip/prot/icmp6.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/dhcp6.h"
#include "lwip/ip.h"
#include "lwip/stats.h"
#include "lwip/dns.h"
#include <string.h>
#ifdef LWIP_HOOK_FILENAME
#include LWIP_HOOK_FILENAME
#endif
#if LWIP_IPV6_DUP_DETECT_ATTEMPTS > IP6_ADDR_TENTATIVE_COUNT_MASK
#error LWIP_IPV6_DUP_DETECT_ATTEMPTS > IP6_ADDR_TENTATIVE_COUNT_MASK
#endif
/* 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 netif_addr_idx_t nd6_cached_destination_index;
/* Multicast address holder. */
static ip6_addr_t multicast_address;
static u8_t nd6_tmr_rs_reduction;
/* Static buffer to parse RA packet options */
union ra_options {
struct lladdr_option lladdr;
struct mtu_option mtu;
struct prefix_option prefix;
#if LWIP_ND6_RDNSS_MAX_DNS_SERVERS
struct rdnss_option rdnss;
#endif
};
static union ra_options nd6_ra_buffer;
/* 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 s16_t nd6_find_destination_cache_entry(const ip6_addr_t *ip6addr);
static s16_t nd6_new_destination_cache_entry(void);
static int nd6_is_prefix_in_netif(const ip6_addr_t *ip6addr, struct netif *netif);
static s8_t nd6_select_router(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(const ip6_addr_t *prefix, struct netif *netif);
static s8_t nd6_new_onlink_prefix(const ip6_addr_t *prefix, struct netif *netif);
static s8_t nd6_get_next_hop_entry(const ip6_addr_t *ip6addr, struct netif *netif);
static err_t nd6_queue_packet(s8_t neighbor_index, struct pbuf *q);
#define ND6_SEND_FLAG_MULTICAST_DEST 0x01
#define ND6_SEND_FLAG_ALLNODES_DEST 0x02
#define ND6_SEND_FLAG_ANY_SRC 0x04
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);
static void nd6_send_neighbor_cache_probe(struct nd6_neighbor_cache_entry *entry, 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);
/**
* A local address has been determined to be a duplicate. Take the appropriate
* action(s) on the address and the interface as a whole.
*
* @param netif the netif that owns the address
* @param addr_idx the index of the address detected to be a duplicate
*/
static void
nd6_duplicate_addr_detected(struct netif *netif, s8_t addr_idx)
{
/* Mark the address as duplicate, but leave its lifetimes alone. If this was
* a manually assigned address, it will remain in existence as duplicate, and
* as such be unusable for any practical purposes until manual intervention.
* If this was an autogenerated address, the address will follow normal
* expiration rules, and thus disappear once its valid lifetime expires. */
netif_ip6_addr_set_state(netif, addr_idx, IP6_ADDR_DUPLICATED);
#if LWIP_IPV6_AUTOCONFIG
/* If the affected address was the link-local address that we use to generate
* all other addresses, then we should not continue to use those derived
* addresses either, so mark them as duplicate as well. For autoconfig-only
* setups, this will make the interface effectively unusable, approaching the
* intention of RFC 4862 Sec. 5.4.5. @todo implement the full requirements */
if (addr_idx == 0) {
s8_t i;
for (i = 1; i < LWIP_IPV6_NUM_ADDRESSES; i++) {
if (!ip6_addr_isinvalid(netif_ip6_addr_state(netif, i)) &&
!netif_ip6_addr_isstatic(netif, i)) {
netif_ip6_addr_set_state(netif, i, IP6_ADDR_DUPLICATED);
}
}
}
#endif /* LWIP_IPV6_AUTOCONFIG */
}
#if LWIP_IPV6_AUTOCONFIG
/**
* We received a router advertisement that contains a prefix with the
* autoconfiguration flag set. Add or update an associated autogenerated
* address.
*
* @param netif the netif on which the router advertisement arrived
* @param prefix_opt a pointer to the prefix option data
* @param prefix_addr an aligned copy of the prefix address
*/
static void
nd6_process_autoconfig_prefix(struct netif *netif,
struct prefix_option *prefix_opt, const ip6_addr_t *prefix_addr)
{
ip6_addr_t ip6addr;
u32_t valid_life, pref_life;
u8_t addr_state;
s8_t i, free_idx;
/* The caller already checks RFC 4862 Sec. 5.5.3 points (a) and (b). We do
* the rest, starting with checks for (c) and (d) here. */
valid_life = lwip_htonl(prefix_opt->valid_lifetime);
pref_life = lwip_htonl(prefix_opt->preferred_lifetime);
if (pref_life > valid_life || prefix_opt->prefix_length != 64) {
return; /* silently ignore this prefix for autoconfiguration purposes */
}
/* If an autogenerated address already exists for this prefix, update its
* lifetimes. An address is considered autogenerated if 1) it is not static
* (i.e., manually assigned), and 2) there is an advertised autoconfiguration
* prefix for it (the one we are processing here). This does not necessarily
* exclude the possibility that the address was actually assigned by, say,
* DHCPv6. If that distinction becomes important in the future, more state
* must be kept. As explained elsewhere we also update lifetimes of tentative
* and duplicate addresses. Skip address slot 0 (the link-local address). */
for (i = 1; i < LWIP_IPV6_NUM_ADDRESSES; i++) {
addr_state = netif_ip6_addr_state(netif, i);
if (!ip6_addr_isinvalid(addr_state) && !netif_ip6_addr_isstatic(netif, i) &&
ip6_addr_netcmp(prefix_addr, netif_ip6_addr(netif, i))) {
/* Update the valid lifetime, as per RFC 4862 Sec. 5.5.3 point (e).
* The valid lifetime will never drop to zero as a result of this. */
u32_t remaining_life = netif_ip6_addr_valid_life(netif, i);
if (valid_life > ND6_2HRS || valid_life > remaining_life) {
netif_ip6_addr_set_valid_life(netif, i, valid_life);
} else if (remaining_life > ND6_2HRS) {
netif_ip6_addr_set_valid_life(netif, i, ND6_2HRS);
}
LWIP_ASSERT("bad valid lifetime", !netif_ip6_addr_isstatic(netif, i));
/* Update the preferred lifetime. No bounds checks are needed here. In
* rare cases the advertisement may un-deprecate the address, though.
* Deprecation is left to the timer code where it is handled anyway. */
if (pref_life > 0 && addr_state == IP6_ADDR_DEPRECATED) {
netif_ip6_addr_set_state(netif, i, IP6_ADDR_PREFERRED);
}
netif_ip6_addr_set_pref_life(netif, i, pref_life);
return; /* there should be at most one matching address */
}
}
/* No autogenerated address exists for this prefix yet. See if we can add a
* new one. However, if IPv6 autoconfiguration is administratively disabled,
* do not generate new addresses, but do keep updating lifetimes for existing
* addresses. Also, when adding new addresses, we must protect explicitly
* against a valid lifetime of zero, because again, we use that as a special
* value. The generated address would otherwise expire immediately anyway.
* Finally, the original link-local address must be usable at all. We start
* creating addresses even if the link-local address is still in tentative
* state though, and deal with the fallout of that upon DAD collision. */
addr_state = netif_ip6_addr_state(netif, 0);
if (!netif->ip6_autoconfig_enabled || valid_life == IP6_ADDR_LIFE_STATIC ||
ip6_addr_isinvalid(addr_state) || ip6_addr_isduplicated(addr_state)) {
return;
}
/* Construct the new address that we intend to use, and then see if that
* address really does not exist. It might have been added manually, after
* all. As a side effect, find a free slot. Note that we cannot use
* netif_add_ip6_address() here, as it would return ERR_OK if the address
* already did exist, resulting in that address being given lifetimes. */
IP6_ADDR(&ip6addr, prefix_addr->addr[0], prefix_addr->addr[1],
netif_ip6_addr(netif, 0)->addr[2], netif_ip6_addr(netif, 0)->addr[3]);
ip6_addr_assign_zone(&ip6addr, IP6_UNICAST, netif);
free_idx = 0;
for (i = 1; i < LWIP_IPV6_NUM_ADDRESSES; i++) {
if (!ip6_addr_isinvalid(netif_ip6_addr_state(netif, i))) {
if (ip6_addr_cmp(&ip6addr, netif_ip6_addr(netif, i))) {
return; /* formed address already exists */
}
} else if (free_idx == 0) {
free_idx = i;
}
}
if (free_idx == 0) {
return; /* no address slots available, try again on next advertisement */
}
/* Assign the new address to the interface. */
ip_addr_copy_from_ip6(netif->ip6_addr[free_idx], ip6addr);
netif_ip6_addr_set_valid_life(netif, free_idx, valid_life);
netif_ip6_addr_set_pref_life(netif, free_idx, pref_life);
netif_ip6_addr_set_state(netif, free_idx, IP6_ADDR_TENTATIVE);
}
#endif /* LWIP_IPV6_AUTOCONFIG */
/**
* 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;
s16_t dest_idx;
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;
ip6_addr_t target_address;
/* 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;
/* Create an aligned, zoned copy of the target address. */
ip6_addr_copy_from_packed(target_address, na_hdr->target_address);
ip6_addr_assign_zone(&target_address, IP6_UNICAST, inp);
/* Check a subset of the other RFC 4861 Sec. 7.1.2 requirements. */
if (IP6H_HOPLIM(ip6_current_header()) != ND6_HOPLIM || na_hdr->code != 0 ||
ip6_addr_ismulticast(&target_address)) {
pbuf_free(p);
ND6_STATS_INC(nd6.proterr);
ND6_STATS_INC(nd6.drop);
return;
}
/* @todo RFC MUST: if IP destination is multicast, Solicited flag is zero */
/* @todo RFC MUST: all included options have a length greater than zero */
/* Unsolicited NA?*/
if (ip6_addr_ismulticast(ip6_current_dest_addr())) {
/* This is an unsolicited NA.
* link-layer changed?
* part of DAD mechanism? */
#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_isduplicated(netif_ip6_addr_state(inp, i)) &&
ip6_addr_cmp(&target_address, netif_ip6_addr(inp, i))) {
/* We are using a duplicate address. */
nd6_duplicate_addr_detected(inp, i);
pbuf_free(p);
return;
}
}
#endif /* LWIP_IPV6_DUP_DETECT_ATTEMPTS */
/* 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;
}
/* This is an unsolicited NA, most likely there was a LLADDR change. */
i = nd6_find_neighbor_cache_entry(&target_address);
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? */
/* Find the cache entry corresponding to this na. */
i = nd6_find_neighbor_cache_entry(&target_address);
if (i < 0) {
/* We no longer care about this target address. drop it. */
pbuf_free(p);
return;
}
/* Update cache entry. */
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].netif = inp;
neighbor_cache[i].state = ND6_REACHABLE;
neighbor_cache[i].counter.reachable_time = reachable_time;
/* 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;
ip6_addr_t target_address;
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;
/* Create an aligned, zoned copy of the target address. */
ip6_addr_copy_from_packed(target_address, ns_hdr->target_address);
ip6_addr_assign_zone(&target_address, IP6_UNICAST, inp);
/* Check a subset of the other RFC 4861 Sec. 7.1.1 requirements. */
if (IP6H_HOPLIM(ip6_current_header()) != ND6_HOPLIM || ns_hdr->code != 0 ||
ip6_addr_ismulticast(&target_address)) {
pbuf_free(p);
ND6_STATS_INC(nd6.proterr);
ND6_STATS_INC(nd6.drop);
return;
}
/* @todo RFC MUST: all included options have a length greater than zero */
/* @todo RFC MUST: if IP source is 'any', destination is solicited-node multicast address */
/* @todo RFC MUST: if IP source is 'any', there is no source LL address option */
/* 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(&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(&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. */
nd6_duplicate_addr_detected(inp, i);
}
}
}
} 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 / ND6_TMR_INTERVAL;
}
} 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 / ND6_TMR_INTERVAL;
}
/* Send back a NA for us. Allocate the reply pbuf. */
nd6_send_na(inp, &target_address, 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;
#if LWIP_ND6_RDNSS_MAX_DNS_SERVERS
/* There can be multiple RDNSS options per RA */
u8_t rdnss_server_idx = 0;
#endif /* LWIP_ND6_RDNSS_MAX_DNS_SERVERS */
/* 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;
/* Check a subset of the other RFC 4861 Sec. 6.1.2 requirements. */
if (!ip6_addr_islinklocal(ip6_current_src_addr()) ||
IP6H_HOPLIM(ip6_current_header()) != ND6_HOPLIM || ra_hdr->code != 0) {
pbuf_free(p);
ND6_STATS_INC(nd6.proterr);
ND6_STATS_INC(nd6.drop);
return;
}
/* @todo RFC MUST: all included options have a length greater than zero */
/* If we are sending RS messages, stop. */
#if LWIP_IPV6_SEND_ROUTER_SOLICIT
/* ensure at least one solicitation is sent (see RFC 4861, ch. 6.3.7) */
if ((inp->rs_count < LWIP_ND6_MAX_MULTICAST_SOLICIT) ||
(nd6_send_rs(inp) == ERR_OK)) {
inp->rs_count = 0;
} else {
inp->rs_count = 1;
}
#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 = lwip_htons(ra_hdr->router_lifetime);
/* Re-set default timer values. */
#if LWIP_ND6_ALLOW_RA_UPDATES
if (ra_hdr->retrans_timer > 0) {
retrans_timer = lwip_htonl(ra_hdr->retrans_timer);
}
if (ra_hdr->reachable_time > 0) {
reachable_time = lwip_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;
#if LWIP_IPV6_DHCP6
/* Trigger DHCPv6 if enabled */
dhcp6_nd6_ra_trigger(inp, ra_hdr->flags & ND6_RA_FLAG_MANAGED_ADDR_CONFIG,
ra_hdr->flags & ND6_RA_FLAG_OTHER_CONFIG);
#endif
/* Offset to options. */
offset = sizeof(struct ra_header);
/* Process each option. */
while ((p->tot_len - offset) >= 2) {
u8_t option_type;
u16_t option_len;
int option_len8 = pbuf_try_get_at(p, offset + 1);
if (option_len8 <= 0) {
/* read beyond end or zero length */
goto lenerr_drop_free_return;
}
option_len = ((u8_t)option_len8) << 3;
if (option_len > p->tot_len - offset) {
/* short packet (option does not fit in) */
goto lenerr_drop_free_return;
}
if (p->len == p->tot_len) {
/* no need to copy from contiguous pbuf */
buffer = &((u8_t*)p->payload)[offset];
} else {
/* check if this option fits into our buffer */
if (option_len > sizeof(nd6_ra_buffer)) {
option_type = pbuf_get_at(p, offset);
/* invalid option length */
if (option_type != ND6_OPTION_TYPE_RDNSS) {
goto lenerr_drop_free_return;
}
/* we allow RDNSS option to be longer - we'll just drop some servers */
option_len = sizeof(nd6_ra_buffer);
}
buffer = (u8_t*)&nd6_ra_buffer;
option_len = pbuf_copy_partial(p, &nd6_ra_buffer, option_len, offset);
}
option_type = buffer[0];
switch (option_type) {
case ND6_OPTION_TYPE_SOURCE_LLADDR:
{
struct lladdr_option *lladdr_opt;
if (option_len < sizeof(struct lladdr_option)) {
goto lenerr_drop_free_return;
}
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;
u32_t mtu32;
if (option_len < sizeof(struct mtu_option)) {
goto lenerr_drop_free_return;
}
mtu_opt = (struct mtu_option *)buffer;
mtu32 = lwip_htonl(mtu_opt->mtu);
if ((mtu32 >= IP6_MIN_MTU_LENGTH) && (mtu32 <= 0xffff)) {
#if LWIP_ND6_ALLOW_RA_UPDATES
if (inp->mtu) {
/* don't set the mtu for IPv6 higher than the netif driver supports */
inp->mtu6 = LWIP_MIN(LWIP_MIN(inp->mtu, inp->mtu6), (u16_t)mtu32);
} else {
inp->mtu6 = (u16_t)mtu32;
}
#endif /* LWIP_ND6_ALLOW_RA_UPDATES */
}
break;
}
case ND6_OPTION_TYPE_PREFIX_INFO:
{
struct prefix_option *prefix_opt;
ip6_addr_t prefix_addr;
if (option_len < sizeof(struct prefix_option)) {
goto lenerr_drop_free_return;
}
prefix_opt = (struct prefix_option *)buffer;
/* Get a memory-aligned copy of the prefix. */
ip6_addr_copy_from_packed(prefix_addr, prefix_opt->prefix);
ip6_addr_assign_zone(&prefix_addr, IP6_UNICAST, inp);
if (!ip6_addr_islinklocal(&prefix_addr)) {
if ((prefix_opt->flags & ND6_PREFIX_FLAG_ON_LINK) &&
(prefix_opt->prefix_length == 64)) {
/* Add to on-link prefix list. */
u32_t valid_life;
s8_t prefix;
valid_life = lwip_htonl(prefix_opt->valid_lifetime);
/* find cache entry for this prefix. */
prefix = nd6_get_onlink_prefix(&prefix_addr, inp);
if (prefix < 0 && valid_life > 0) {
/* Create a new cache entry. */
prefix = nd6_new_onlink_prefix(&prefix_addr, inp);
}
if (prefix >= 0) {
prefix_list[prefix].invalidation_timer = valid_life;
}
}
#if LWIP_IPV6_AUTOCONFIG
if (prefix_opt->flags & ND6_PREFIX_FLAG_AUTONOMOUS) {
/* Perform processing for autoconfiguration. */
nd6_process_autoconfig_prefix(inp, prefix_opt, &prefix_addr);
}
#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;
#if LWIP_ND6_RDNSS_MAX_DNS_SERVERS
case ND6_OPTION_TYPE_RDNSS:
{
u8_t num, n;
u16_t copy_offset = offset + SIZEOF_RDNSS_OPTION_BASE;
struct rdnss_option * rdnss_opt;
if (option_len < SIZEOF_RDNSS_OPTION_BASE) {
goto lenerr_drop_free_return;
}
rdnss_opt = (struct rdnss_option *)buffer;
num = (rdnss_opt->length - 1) / 2;
for (n = 0; (rdnss_server_idx < DNS_MAX_SERVERS) && (n < num); n++, copy_offset += sizeof(ip6_addr_p_t)) {
ip_addr_t rdnss_address;
/* Copy directly from pbuf to get an aligned, zoned copy of the prefix. */
if (pbuf_copy_partial(p, &rdnss_address, sizeof(ip6_addr_p_t), copy_offset) == sizeof(ip6_addr_p_t)) {
IP_SET_TYPE_VAL(rdnss_address, IPADDR_TYPE_V6);
ip6_addr_assign_zone(ip_2_ip6(&rdnss_address), IP6_UNKNOWN, inp);
if (htonl(rdnss_opt->lifetime) > 0) {
/* TODO implement Lifetime > 0 */
dns_setserver(rdnss_server_idx++, &rdnss_address);
} else {
/* TODO implement DNS removal in dns.c */
u8_t s;
for (s = 0; s < DNS_MAX_SERVERS; s++) {
const ip_addr_t *addr = dns_getserver(s);
if(ip_addr_cmp(addr, &rdnss_address)) {
dns_setserver(s, NULL);
}
}
}
}
}
break;
}
#endif /* LWIP_ND6_RDNSS_MAX_DNS_SERVERS */
default:
/* Unrecognized option, abort. */
ND6_STATS_INC(nd6.proterr);
break;
}
/* option length is checked earlier to be non-zero to make sure loop ends */
offset += 8 * (u8_t)option_len8;
}
break; /* ICMP6_TYPE_RA */
}
case ICMP6_TYPE_RD: /* Redirect */
{
struct redirect_header *redir_hdr;
struct lladdr_option *lladdr_opt;
ip6_addr_t destination_address, target_address;
/* 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;
/* Create an aligned, zoned copy of the destination address. */
ip6_addr_copy_from_packed(destination_address, redir_hdr->destination_address);
ip6_addr_assign_zone(&destination_address, IP6_UNICAST, inp);
/* Check a subset of the other RFC 4861 Sec. 8.1 requirements. */
if (!ip6_addr_islinklocal(ip6_current_src_addr()) ||
IP6H_HOPLIM(ip6_current_header()) != ND6_HOPLIM ||
redir_hdr->code != 0 || ip6_addr_ismulticast(&destination_address)) {
pbuf_free(p);
ND6_STATS_INC(nd6.proterr);
ND6_STATS_INC(nd6.drop);
return;
}
/* @todo RFC MUST: IP source address equals first-hop router for destination_address */
/* @todo RFC MUST: ICMP target address is either link-local address or same as destination_address */
/* @todo RFC MUST: all included options have a length greater than zero */
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;
}
/* Find dest address in cache */
dest_idx = nd6_find_destination_cache_entry(&destination_address);
if (dest_idx < 0) {
/* Destination not in cache, drop packet. */
pbuf_free(p);
return;
}
/* Create an aligned, zoned copy of the target address. */
ip6_addr_copy_from_packed(target_address, redir_hdr->target_address);
ip6_addr_assign_zone(&target_address, IP6_UNICAST, inp);
/* Set the new target address. */
ip6_addr_copy(destination_cache[dest_idx].next_hop_addr, 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) {
i = nd6_find_neighbor_cache_entry(&target_address);
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_copy(neighbor_cache[i].next_hop_address, target_address);
/* 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 / ND6_TMR_INTERVAL;
}
}
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 / ND6_TMR_INTERVAL;
}
}
}
}
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;
ip6_addr_t destination_address;
/* 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));
/* Create an aligned, zoned copy of the destination address. */
ip6_addr_copy_from_packed(destination_address, ip6hdr->dest);
ip6_addr_assign_zone(&destination_address, IP6_UNKNOWN, inp);
/* Look for entry in destination cache. */
dest_idx = nd6_find_destination_cache_entry(&destination_address);
if (dest_idx < 0) {
/* Destination not in cache, drop packet. */
pbuf_free(p);
return;
}
/* Change the Path MTU. */
pmtu = lwip_htonl(icmp6hdr->data);
destination_cache[dest_idx].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);
return;
lenerr_drop_free_return:
ND6_STATS_INC(nd6.lenerr);
ND6_STATS_INC(nd6.drop);
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
* - Update lifetimes of our addresses
* - 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_neighbor_cache_probe(&neighbor_cache[i], 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++;
break;
case ND6_DELAY:
if (neighbor_cache[i].counter.delay_time <= 1) {
/* Change to PROBE state. */
neighbor_cache[i].state = ND6_PROBE;
neighbor_cache[i].counter.probes_sent = 0;
} else {
neighbor_cache[i].counter.delay_time--;
}
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_neighbor_cache_probe(&neighbor_cache[i], 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 <= ND6_TMR_INTERVAL / 1000) {
/* No more than 1 second remaining. Clear this entry. Also clear any of
* its destination cache entries, as per RFC 4861 Sec. 5.3 and 6.3.5. */
s8_t j;
for (j = 0; j < LWIP_ND6_NUM_DESTINATIONS; j++) {
if (ip6_addr_cmp(&destination_cache[j].next_hop_addr,
&default_router_list[i].neighbor_entry->next_hop_address)) {
ip6_addr_set_any(&destination_cache[j].destination_addr);
}
}
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;
} else {
default_router_list[i].invalidation_timer -= ND6_TMR_INTERVAL / 1000;
}
}
}
/* 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;
prefix_list[i].netif = NULL;
} else {
prefix_list[i].invalidation_timer -= ND6_TMR_INTERVAL / 1000;
}
}
}
/* Process our own addresses, updating address lifetimes and/or DAD state. */
NETIF_FOREACH(netif) {
for (i = 0; i < LWIP_IPV6_NUM_ADDRESSES; ++i) {
u8_t addr_state;
#if LWIP_IPV6_ADDRESS_LIFETIMES
/* Step 1: update address lifetimes (valid and preferred). */
addr_state = netif_ip6_addr_state(netif, i);
/* RFC 4862 is not entirely clear as to whether address lifetimes affect
* tentative addresses, and is even less clear as to what should happen
* with duplicate addresses. We choose to track and update lifetimes for
* both those types, although for different reasons:
* - for tentative addresses, the line of thought of Sec. 5.7 combined
* with the potentially long period that an address may be in tentative
* state (due to the interface being down) suggests that lifetimes
* should be independent of external factors which would include DAD;
* - for duplicate addresses, retiring them early could result in a new
* but unwanted attempt at marking them as valid, while retiring them
* late/never could clog up address slots on the netif.
* As a result, we may end up expiring addresses of either type here.
*/
if (!ip6_addr_isinvalid(addr_state) &&
!netif_ip6_addr_isstatic(netif, i)) {
u32_t life = netif_ip6_addr_valid_life(netif, i);
if (life <= ND6_TMR_INTERVAL / 1000) {
/* The address has expired. */
netif_ip6_addr_set_valid_life(netif, i, 0);
netif_ip6_addr_set_pref_life(netif, i, 0);
netif_ip6_addr_set_state(netif, i, IP6_ADDR_INVALID);
} else {
if (!ip6_addr_life_isinfinite(life)) {
life -= ND6_TMR_INTERVAL / 1000;
LWIP_ASSERT("bad valid lifetime", life != IP6_ADDR_LIFE_STATIC);
netif_ip6_addr_set_valid_life(netif, i, life);
}
/* The address is still here. Update the preferred lifetime too. */
life = netif_ip6_addr_pref_life(netif, i);
if (life <= ND6_TMR_INTERVAL / 1000) {
/* This case must also trigger if 'life' was already zero, so as to
* deal correctly with advertised preferred-lifetime reductions. */
netif_ip6_addr_set_pref_life(netif, i, 0);
if (addr_state == IP6_ADDR_PREFERRED)
netif_ip6_addr_set_state(netif, i, IP6_ADDR_DEPRECATED);
} else if (!ip6_addr_life_isinfinite(life)) {
life -= ND6_TMR_INTERVAL / 1000;
netif_ip6_addr_set_pref_life(netif, i, life);
}
}
}
/* The address state may now have changed, so reobtain it next. */
#endif /* LWIP_IPV6_ADDRESS_LIFETIMES */
/* Step 2: update DAD state. */
addr_state = netif_ip6_addr_state(netif, i);
if (ip6_addr_istentative(addr_state)) {
if ((addr_state & IP6_ADDR_TENTATIVE_COUNT_MASK) >= LWIP_IPV6_DUP_DETECT_ATTEMPTS) {
/* No NA received in response. Mark address as valid. For dynamic
* addresses with an expired preferred lifetime, the state is set to
* deprecated right away. That should almost never happen, though. */
addr_state = IP6_ADDR_PREFERRED;
#if LWIP_IPV6_ADDRESS_LIFETIMES
if (!netif_ip6_addr_isstatic(netif, i) &&
netif_ip6_addr_pref_life(netif, i) == 0) {
addr_state = IP6_ADDR_DEPRECATED;
}
#endif /* LWIP_IPV6_ADDRESS_LIFETIMES */
netif_ip6_addr_set_state(netif, i, addr_state);
} else if (netif_is_up(netif) && netif_is_link_up(netif)) {
/* tentative: set next state by increasing by one */
netif_ip6_addr_set_state(netif, i, addr_state + 1);
/* Send a NS for this address. Use the unspecified address as source
* address in all cases (RFC 4862 Sec. 5.4.2), not in the least
* because as it is, we only consider multicast replies for DAD. */
nd6_send_ns(netif, netif_ip6_addr(netif, i),
ND6_SEND_FLAG_MULTICAST_DEST | ND6_SEND_FLAG_ANY_SRC);
}
}
}
}
#if LWIP_IPV6_SEND_ROUTER_SOLICIT
/* Send router solicitation messages, if necessary. */
if (!nd6_tmr_rs_reduction) {
nd6_tmr_rs_reduction = (ND6_RTR_SOLICITATION_INTERVAL / ND6_TMR_INTERVAL) - 1;
NETIF_FOREACH(netif) {
if ((netif->rs_count > 0) && netif_is_up(netif) &&
netif_is_link_up(netif) &&
!ip6_addr_isinvalid(netif_ip6_addr_state(netif, 0)) &&
!ip6_addr_isduplicated(netif_ip6_addr_state(netif, 0))) {
if (nd6_send_rs(netif) == ERR_OK) {
netif->rs_count--;
}
}
}
} else {
nd6_tmr_rs_reduction--;
}
#endif /* LWIP_IPV6_SEND_ROUTER_SOLICIT */
}
/** Send a neighbor solicitation message for a specific neighbor cache entry
*
* @param entry the neightbor cache entry for wich to send the message
* @param flags one of ND6_SEND_FLAG_*
*/
static void
nd6_send_neighbor_cache_probe(struct nd6_neighbor_cache_entry *entry, u8_t flags)
{
nd6_send_ns(entry->netif, &entry->next_hop_address, flags);
}
/**
* 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 pbuf *p;
const ip6_addr_t *src_addr = NULL;
u16_t lladdr_opt_len;
LWIP_ASSERT("target address is required", target_addr != NULL);
if (!(flags & ND6_SEND_FLAG_ANY_SRC)) {
int i;
for (i = 0; i < LWIP_IPV6_NUM_ADDRESSES; i++) {
if (ip6_addr_isvalid(netif_ip6_addr_state(netif, i)) &&
ip6_addr_netcmp(target_addr, netif_ip6_addr(netif, i))) {
src_addr = netif_ip6_addr(netif, i);
break;
}
}
if (i == LWIP_IPV6_NUM_ADDRESSES) {
LWIP_DEBUGF(IP6_DEBUG | LWIP_DBG_LEVEL_WARNING, ("ICMPv6 NS: no available src address\n"));
ND6_STATS_INC(nd6.err);
return;
}
/* calculate option length (in 8-byte-blocks) */
lladdr_opt_len = ((netif->hwaddr_len + 2) + 7) >> 3;
} else {
src_addr = IP6_ADDR_ANY6;
/* Option "MUST NOT be included when the source IP address is the unspecified address." */
lladdr_opt_len = 0;
}
/* Allocate a packet. */
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;
ns_hdr->type = ICMP6_TYPE_NS;
ns_hdr->code = 0;
ns_hdr->chksum = 0;
ns_hdr->reserved = 0;
ip6_addr_copy_to_packed(ns_hdr->target_address, *target_addr);
if (lladdr_opt_len != 0) {
struct lladdr_option *lladdr_opt = (struct lladdr_option *)((u8_t*)p->payload + sizeof(struct ns_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);
}
/* 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]);
ip6_addr_assign_zone(&multicast_address, IP6_MULTICAST, netif);
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,
ND6_HOPLIM, 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;
LWIP_ASSERT("target address is required", target_addr != NULL);
/* Use link-local address as source address. */
/* src_addr = netif_ip6_addr(netif, 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_copy_to_packed(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]);
ip6_addr_assign_zone(&multicast_address, IP6_MULTICAST, netif);
dest_addr = &multicast_address;
} else if (flags & ND6_SEND_FLAG_ALLNODES_DEST) {
ip6_addr_set_allnodes_linklocal(&multicast_address);
ip6_addr_assign_zone(&multicast_address, IP6_MULTICAST, netif);
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,
ND6_HOPLIM, 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);
ip6_addr_assign_zone(&multicast_address, IP6_MULTICAST, netif);
/* 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,
ND6_HOPLIM, 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 s16_t
nd6_find_destination_cache_entry(const ip6_addr_t *ip6addr)
{
s16_t i;
IP6_ADDR_ZONECHECK(ip6addr);
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 s16_t
nd6_new_destination_cache_entry(void)
{
s16_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;
}
/**
* Clear the destination cache.
*
* This operation may be necessary for consistency in the light of changing
* local addresses and/or use of the gateway hook.
*/
void
nd6_clear_destination_cache(void)
{
int i;
for (i = 0; i < LWIP_ND6_NUM_DESTINATIONS; i++) {
ip6_addr_set_any(&destination_cache[i].destination_addr);
}
}
/**
* Determine whether an address matches an on-link prefix or the subnet of a
* statically assigned address.
*
* @param ip6addr the IPv6 address to match
* @return 1 if the address is on-link, 0 otherwise
*/
static int
nd6_is_prefix_in_netif(const ip6_addr_t *ip6addr, struct netif *netif)
{
s8_t i;
/* Check to see if the address matches an on-link prefix. */
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 (= static)
* address. Static addresses have an implied /64 subnet assignment. Dynamic
* addresses (from autoconfiguration) have no implied subnet assignment, and
* are thus effectively /128 assignments. See RFC 5942 for more on this. */
for (i = 0; i < LWIP_IPV6_NUM_ADDRESSES; i++) {
if (ip6_addr_isvalid(netif_ip6_addr_state(netif, i)) &&
netif_ip6_addr_isstatic(netif, i) &&
ip6_addr_netcmp(ip6addr, netif_ip6_addr(netif, i))) {
return 1;
}
}
return 0;
}
/**
* Select a default router for a destination.
*
* This function is used both for routing and for finding a next-hop target for
* a packet. In the former case, the given netif is NULL, and the returned
* router entry must be for a netif suitable for sending packets (up, link up).
* In the latter case, the given netif is not NULL and restricts router choice.
*
* @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
*/
static s8_t
nd6_select_router(const ip6_addr_t *ip6addr, struct netif *netif)
{
struct netif *router_netif;
s8_t i, j, valid_router;
static s8_t last_router;
LWIP_UNUSED_ARG(ip6addr); /* @todo match preferred routes!! (must implement ND6_OPTION_TYPE_ROUTE_INFO) */
/* @todo: implement default router preference */
/* Look for valid routers. A reachable router is preferred. */
valid_router = -1;
for (i = 0; i < LWIP_ND6_NUM_ROUTERS; i++) {
/* Is the router netif both set and apppropriate? */
if (default_router_list[i].neighbor_entry != NULL) {
router_netif = default_router_list[i].neighbor_entry->netif;
if ((router_netif != NULL) && (netif != NULL ? netif == router_netif :
(netif_is_up(router_netif) && netif_is_link_up(router_netif)))) {
/* Is the router valid, i.e., reachable or probably reachable as per
* RFC 4861 Sec. 6.3.6? Note that we will never return a router that
* has no neighbor cache entry, due to the netif association tests. */
if (default_router_list[i].neighbor_entry->state != ND6_INCOMPLETE) {
/* Is the router known to be reachable? */
if (default_router_list[i].neighbor_entry->state == ND6_REACHABLE) {
return i; /* valid and reachable - done! */
} else if (valid_router < 0) {
valid_router = i; /* valid but not known to be reachable */
}
}
}
}
}
if (valid_router >= 0) {
return valid_router;
}
/* Look for any router for which we have any information at all. */
/* last_router is used for round-robin selection of incomplete routers, as
* recommended in RFC 4861 Sec. 6.3.6 point (2). Advance only when picking a
* route, to select the same router as next-hop target in the common case. */
if ((netif == NULL) && (++last_router >= LWIP_ND6_NUM_ROUTERS)) {
last_router = 0;
}
i = last_router;
for (j = 0; j < LWIP_ND6_NUM_ROUTERS; j++) {
if (default_router_list[i].neighbor_entry != NULL) {
router_netif = default_router_list[i].neighbor_entry->netif;
if ((router_netif != NULL) && (netif != NULL ? netif == router_netif :
(netif_is_up(router_netif) && netif_is_link_up(router_netif)))) {
return i;
}
}
if (++i >= LWIP_ND6_NUM_ROUTERS) {
i = 0;
}
}
/* no suitable router found. */
return -1;
}
/**
* Find a router-announced route to the given destination. This route may be
* based on an on-link prefix or a default router.
*
* If a suitable route is found, the returned netif is guaranteed to be in a
* suitable state (up, link up) to be used for packet transmission.
*
* @param ip6addr the destination IPv6 address
* @return the netif to use for the destination, or NULL if none found
*/
struct netif *
nd6_find_route(const ip6_addr_t *ip6addr)
{
struct netif *netif;
s8_t i;
/* @todo decide if it makes sense to check the destination cache first */
/* Check if there is a matching on-link prefix. There may be multiple
* matches. Pick the first one that is associated with a suitable netif. */
for (i = 0; i < LWIP_ND6_NUM_PREFIXES; ++i) {
netif = prefix_list[i].netif;
if ((netif != NULL) && ip6_addr_netcmp(&prefix_list[i].prefix, ip6addr) &&
netif_is_up(netif) && netif_is_link_up(netif)) {
return netif;
}
}
/* No on-link prefix match. Find a router that can forward the packet. */
i = nd6_select_router(ip6addr, NULL);
if (i >= 0) {
LWIP_ASSERT("selected router must have a neighbor entry",
default_router_list[i].neighbor_entry != NULL);
return default_router_list[i].neighbor_entry->netif;
}
return NULL;
}
/**
* 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;
IP6_ADDR_ZONECHECK_NETIF(router_addr, netif);
/* 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 free_router_index;
s8_t neighbor_index;
IP6_ADDR_ZONECHECK_NETIF(router_addr, netif);
/* 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 = 1;
nd6_send_neighbor_cache_probe(&neighbor_cache[neighbor_index], ND6_SEND_FLAG_MULTICAST_DEST);
}
/* Mark neighbor as router. */
neighbor_cache[neighbor_index].isrouter = 1;
/* Look for empty entry. */
free_router_index = LWIP_ND6_NUM_ROUTERS;
for (router_index = LWIP_ND6_NUM_ROUTERS - 1; router_index >= 0; router_index--) {
/* check if router already exists (this is a special case for 2 netifs on the same subnet
- e.g. wifi and cable) */
if(default_router_list[router_index].neighbor_entry == &(neighbor_cache[neighbor_index])){
return router_index;
}
if (default_router_list[router_index].neighbor_entry == NULL) {
/* remember lowest free index to create a new entry */
free_router_index = router_index;
}
}
if (free_router_index < LWIP_ND6_NUM_ROUTERS) {
default_router_list[free_router_index].neighbor_entry = &(neighbor_cache[neighbor_index]);
return free_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(const 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(const 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);
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
*/
static s8_t
nd6_get_next_hop_entry(const ip6_addr_t *ip6addr, struct netif *netif)
{
#ifdef LWIP_HOOK_ND6_GET_GW
const ip6_addr_t *next_hop_addr;
#endif /* LWIP_HOOK_ND6_GET_GW */
s8_t i;
s16_t dst_idx;
IP6_ADDR_ZONECHECK_NETIF(ip6addr, netif);
#if LWIP_NETIF_HWADDRHINT
if (netif->hints != NULL) {
/* per-pcb cached entry was given */
netif_addr_idx_t addr_hint = netif->hints->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. */
dst_idx = nd6_find_destination_cache_entry(ip6addr);
if (dst_idx >= 0) {
/* found destination entry. make it our new cached index. */
LWIP_ASSERT("type overflow", (size_t)dst_idx < NETIF_ADDR_IDX_MAX);
nd6_cached_destination_index = (netif_addr_idx_t)dst_idx;
} else {
/* Not found. Create a new destination entry. */
dst_idx = nd6_new_destination_cache_entry();
if (dst_idx >= 0) {
/* got new destination entry. make it our new cached index. */
LWIP_ASSERT("type overflow", (size_t)dst_idx < NETIF_ADDR_IDX_MAX);
nd6_cached_destination_index = (netif_addr_idx_t)dst_idx;
} 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_mtu6(netif);
ip6_addr_copy(destination_cache[nd6_cached_destination_index].next_hop_addr, destination_cache[nd6_cached_destination_index].destination_addr);
#ifdef LWIP_HOOK_ND6_GET_GW
} else if ((next_hop_addr = LWIP_HOOK_ND6_GET_GW(netif, ip6addr)) != NULL) {
/* Next hop for destination provided by hook function. */
destination_cache[nd6_cached_destination_index].pmtu = netif->mtu;
ip6_addr_set(&destination_cache[nd6_cached_destination_index].next_hop_addr, next_hop_addr);
#endif /* LWIP_HOOK_ND6_GET_GW */
} 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_mtu6(netif); /* 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->hints != NULL) {
/* per-pcb cached entry was given */
netif->hints->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 = 1;
nd6_send_neighbor_cache_probe(&neighbor_cache[i], ND6_SEND_FLAG_MULTICAST_DEST);
}
}
/* 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
*/
static 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 that must be copied, we have to copy the whole chain
* into a new PBUF_RAM. See the definition of PBUF_NEEDS_COPY for details. */
p = q;
while (p) {
if (PBUF_NEEDS_COPY(p)) {
copy_needed = 1;
break;
}
p = p->next;
}
if (copy_needed) {
/* copy the whole packet into new pbufs */
p = pbuf_clone(PBUF_LINK, PBUF_RAM, q);
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_clone(PBUF_LINK, PBUF_RAM, q);
}
} 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;
ip6_addr_t dest;
#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);
/* Create an aligned copy. */
ip6_addr_copy_from_packed(dest, ip6hdr->dest);
/* Restore the zone, if applicable. */
ip6_addr_assign_zone(&dest, IP6_UNKNOWN, neighbor_cache[i].netif);
/* send the queued IPv6 packet */
(neighbor_cache[i].netif)->output_ip6(neighbor_cache[i].netif, q->p, &dest);
/* 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);
/* Create an aligned copy. */
ip6_addr_copy_from_packed(dest, ip6hdr->dest);
/* Restore the zone, if applicable. */
ip6_addr_assign_zone(&dest, IP6_UNKNOWN, neighbor_cache[i].netif);
/* send the queued IPv6 packet */
(neighbor_cache[i].netif)->output_ip6(neighbor_cache[i].netif, neighbor_cache[i].q, &dest);
/* free the queued IP packet */
pbuf_free(neighbor_cache[i].q);
neighbor_cache[i].q = NULL;
}
#endif /* LWIP_ND6_QUEUEING */
}
/**
* A packet is to be transmitted to a specific IPv6 destination on a specific
* interface. Check if we can find the hardware address of the next hop to use
* for the packet. If so, give the hardware address to the caller, which should
* use it to send the packet right away. Otherwise, enqueue the packet for
* later transmission while looking up the hardware address, if possible.
*
* As such, this function returns one of three different possible results:
*
* - ERR_OK with a non-NULL 'hwaddrp': the caller should send the packet now.
* - ERR_OK with a NULL 'hwaddrp': the packet has been enqueued for later.
* - not ERR_OK: something went wrong; forward the error upward in the stack.
*
* @param netif The lwIP network interface on which the IP packet will be sent.
* @param q The pbuf(s) containing the IP packet to be sent.
* @param ip6addr The destination IPv6 address of the packet.
* @param hwaddrp On success, filled with a pointer to a HW address or NULL (meaning
* the packet has been queued).
* @return
* - ERR_OK on success, ERR_RTE if no route was found for the packet,
* or ERR_MEM if low memory conditions prohibit sending the packet at all.
*/
err_t
nd6_get_next_hop_addr_or_queue(struct netif *netif, struct pbuf *q, const ip6_addr_t *ip6addr, const u8_t **hwaddrp)
{
s8_t i;
/* Get next hop record. */
i = nd6_get_next_hop_entry(ip6addr, netif);
if (i < 0) {
/* failed to get a next hop neighbor record. */
return i;
}
/* Now that we have a destination record, send or queue the packet. */
if (neighbor_cache[i].state == ND6_STALE) {
/* Switch to delay state. */
neighbor_cache[i].state = ND6_DELAY;
neighbor_cache[i].counter.delay_time = LWIP_ND6_DELAY_FIRST_PROBE_TIME / ND6_TMR_INTERVAL;
}
/* @todo should we send or queue if PROBE? send for now, to let unicast NS pass. */
if ((neighbor_cache[i].state == ND6_REACHABLE) ||
(neighbor_cache[i].state == ND6_DELAY) ||
(neighbor_cache[i].state == ND6_PROBE)) {
/* Tell the caller to send out the packet now. */
*hwaddrp = neighbor_cache[i].lladdr;
return ERR_OK;
}
/* We should queue packet on this interface. */
*hwaddrp = NULL;
return nd6_queue_packet(i, q);
}
/**
* 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)
{
s16_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_mtu6(netif);
}
return IP6_MIN_MTU_LENGTH; /* 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;
s16_t dst_idx;
/* Find destination in cache. */
if (ip6_addr_cmp(ip6addr, &(destination_cache[nd6_cached_destination_index].destination_addr))) {
dst_idx = nd6_cached_destination_index;
ND6_STATS_INC(nd6.cachehit);
} else {
dst_idx = nd6_find_destination_cache_entry(ip6addr);
}
if (dst_idx < 0) {
return;
}
/* Find next hop neighbor in cache. */
if (ip6_addr_cmp(&(destination_cache[dst_idx].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[dst_idx].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 */
/**
* Remove all prefix, neighbor_cache and router entries of the specified netif.
*
* @param netif points to a network interface
*/
void
nd6_cleanup_netif(struct netif *netif)
{
u8_t i;
s8_t router_index;
for (i = 0; i < LWIP_ND6_NUM_PREFIXES; i++) {
if (prefix_list[i].netif == netif) {
prefix_list[i].netif = NULL;
}
}
for (i = 0; i < LWIP_ND6_NUM_NEIGHBORS; i++) {
if (neighbor_cache[i].netif == netif) {
for (router_index = 0; router_index < LWIP_ND6_NUM_ROUTERS; router_index++) {
if (default_router_list[router_index].neighbor_entry == &neighbor_cache[i]) {
default_router_list[router_index].neighbor_entry = NULL;
default_router_list[router_index].flags = 0;
}
}
neighbor_cache[i].isrouter = 0;
nd6_free_neighbor_cache_entry(i);
}
}
/* Clear the destination cache, since many entries may now have become
* invalid for one of several reasons. As destination cache entries have no
* netif association, use a sledgehammer approach (this can be improved). */
nd6_clear_destination_cache();
}
#if LWIP_IPV6_MLD
/**
* The state of a local IPv6 address entry is about to change. If needed, join
* or leave the solicited-node multicast group for the address.
*
* @param netif The netif that owns the address.
* @param addr_idx The index of the address.
* @param new_state The new (IP6_ADDR_) state for the address.
*/
void
nd6_adjust_mld_membership(struct netif *netif, s8_t addr_idx, u8_t new_state)
{
u8_t old_state, old_member, new_member;
old_state = netif_ip6_addr_state(netif, addr_idx);
/* Determine whether we were, and should be, a member of the solicited-node
* multicast group for this address. For tentative addresses, the group is
* not joined until the address enters the TENTATIVE_1 (or VALID) state. */
old_member = (old_state != IP6_ADDR_INVALID && old_state != IP6_ADDR_DUPLICATED && old_state != IP6_ADDR_TENTATIVE);
new_member = (new_state != IP6_ADDR_INVALID && new_state != IP6_ADDR_DUPLICATED && new_state != IP6_ADDR_TENTATIVE);
if (old_member != new_member) {
ip6_addr_set_solicitednode(&multicast_address, netif_ip6_addr(netif, addr_idx)->addr[3]);
ip6_addr_assign_zone(&multicast_address, IP6_MULTICAST, netif);
if (new_member) {
mld6_joingroup_netif(netif, &multicast_address);
} else {
mld6_leavegroup_netif(netif, &multicast_address);
}
}
}
#endif /* LWIP_IPV6_MLD */
/** Netif was added, set up, or reconnected (link up) */
void
nd6_restart_netif(struct netif *netif)
{
#if LWIP_IPV6_SEND_ROUTER_SOLICIT
/* Send Router Solicitation messages (see RFC 4861, ch. 6.3.7). */
netif->rs_count = LWIP_ND6_MAX_MULTICAST_SOLICIT;
#endif /* LWIP_IPV6_SEND_ROUTER_SOLICIT */
}
#endif /* LWIP_IPV6 */