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RIOT/sys/net/network_layer/ng_ndp/ng_ndp.c
Martine Lenders 6f85433fa8 ng_ndp: fix _get_l2src
2015-07-14 16:30:31 +02:00

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/*
* Copyright (C) 2015 Martine Lenders <mlenders@inf.fu-berlin.de>
*
* This file is subject to the terms and conditions of the GNU Lesser General
* Public License v2.1. See the file LICENSE in the top level directory for
* more details.
*/
/**
* @ingroup net_ng_ndp
* @{
*
* @file
*
* @author Martine Lenders <mlenders@inf.fu-berlin.de>
*/
#include <errno.h>
#include <string.h>
#include "byteorder.h"
#include "net/ng_icmpv6.h"
#include "net/ng_ipv6.h"
#include "net/ng_ipv6/ext/rh.h"
#include "net/ng_netbase.h"
#include "random.h"
#include "utlist.h"
#include "thread.h"
#include "vtimer.h"
#include "net/ng_ndp.h"
#include "net/ng_fib.h"
#define ENABLE_DEBUG (0)
#include "debug.h"
#if ENABLE_DEBUG
/* For PRIu8 etc. */
#include <inttypes.h>
static char addr_str[NG_IPV6_ADDR_MAX_STR_LEN];
#endif
static ng_pktqueue_t _pkt_nodes[NG_IPV6_NC_SIZE * 2];
static ng_ipv6_nc_t *_last_router = NULL; /* last router chosen as default
* router. Only used if reachability
* is suspect (i. e. incomplete or
* not at all) */
/* random helper function */
static inline uint32_t _rand(uint32_t min, uint32_t max)
{
return (genrand_uint32() % (max - min)) + min;
}
static bool _handle_sl2a_opt(kernel_pid_t iface, ng_pktsnip_t *pkt,
ng_ipv6_hdr_t *ipv6, uint8_t icmpv6_type,
ng_ndp_opt_t *sl2a_opt);
static int _handle_tl2a_opt(ng_pktsnip_t *pkt, ng_ipv6_hdr_t *ipv6,
uint8_t icmpv6_type, ng_ndp_opt_t *tl2a_opt,
uint8_t *l2addr);
/* send address resolution messages */
static void _send_nbr_sol(kernel_pid_t iface, ng_ipv6_addr_t *tgt,
ng_ipv6_addr_t *dst);
static void _send_nbr_adv(kernel_pid_t iface, ng_ipv6_addr_t *tgt,
ng_ipv6_addr_t *dst, bool supply_tl2a);
static void _set_state(ng_ipv6_nc_t *nc_entry, uint8_t state);
/* special netapi helper */
static inline void _send_delayed(vtimer_t *t, timex_t interval, ng_pktsnip_t *pkt)
{
vtimer_remove(t);
vtimer_set_msg(t, interval, ng_ipv6_pid, NG_NETAPI_MSG_TYPE_SND, pkt);
}
/* packet queue node allocation */
static ng_pktqueue_t *_alloc_pkt_node(ng_pktsnip_t *pkt);
void ng_ndp_nbr_sol_handle(kernel_pid_t iface, ng_pktsnip_t *pkt,
ng_ipv6_hdr_t *ipv6, ng_ndp_nbr_sol_t *nbr_sol,
size_t icmpv6_size)
{
uint16_t opt_offset = 0;
uint8_t *buf = ((uint8_t *)nbr_sol) + sizeof(ng_ndp_nbr_sol_t);
ng_ipv6_addr_t *tgt;
int sicmpv6_size = (int)icmpv6_size;
DEBUG("ndp: received neighbor solicitation (src: %s, ",
ng_ipv6_addr_to_str(addr_str, &ipv6->src, sizeof(addr_str)));
DEBUG("dst: %s, ",
ng_ipv6_addr_to_str(addr_str, &ipv6->dst, sizeof(addr_str)));
DEBUG("tgt: %s)\n",
ng_ipv6_addr_to_str(addr_str, &nbr_sol->tgt, sizeof(addr_str)));
/* check validity */
if ((ipv6->hl != 255) || (nbr_sol->code != 0) ||
(icmpv6_size < sizeof(ng_ndp_nbr_sol_t)) ||
ng_ipv6_addr_is_multicast(&nbr_sol->tgt) ||
(ng_ipv6_addr_is_unspecified(&ipv6->src) &&
ng_ipv6_addr_is_solicited_node(&ipv6->dst))) {
DEBUG("ndp: neighbor solicitation was invalid.\n");
/* ipv6 releases */
return;
}
if ((tgt = ng_ipv6_netif_find_addr(iface, &nbr_sol->tgt)) == NULL) {
DEBUG("ndp: Target address is not to interface %" PRIkernel_pid "\n",
iface);
/* ipv6 releases */
return;
}
sicmpv6_size -= sizeof(ng_ndp_nbr_sol_t);
while (sicmpv6_size > 0) {
ng_ndp_opt_t *opt = (ng_ndp_opt_t *)(buf + opt_offset);
switch (opt->type) {
case NG_NDP_OPT_SL2A:
if (!_handle_sl2a_opt(iface, pkt, ipv6, nbr_sol->type, opt)) {
/* invalid source link-layer address option */
return;
}
break;
default:
/* silently discard all other options */
break;
}
opt_offset += (opt->len * 8);
sicmpv6_size -= (opt->len * 8);
}
_send_nbr_adv(iface, tgt, &ipv6->src,
ng_ipv6_addr_is_multicast(&ipv6->dst));
return;
}
static inline bool _pkt_has_l2addr(ng_netif_hdr_t *netif_hdr)
{
return (netif_hdr != NULL) && (netif_hdr->src_l2addr_len != 0) &&
(netif_hdr->dst_l2addr_len != 0);
}
void ng_ndp_nbr_adv_handle(kernel_pid_t iface, ng_pktsnip_t *pkt,
ng_ipv6_hdr_t *ipv6, ng_ndp_nbr_adv_t *nbr_adv,
size_t icmpv6_size)
{
uint16_t opt_offset = 0;
uint8_t *buf = ((uint8_t *)nbr_adv) + sizeof(ng_ndp_nbr_adv_t);
int l2tgt_len = 0;
uint8_t l2tgt[NG_IPV6_NC_L2_ADDR_MAX];
int sicmpv6_size = (int)icmpv6_size;
ng_ipv6_nc_t *nc_entry = ng_ipv6_nc_get(iface, &nbr_adv->tgt);
ng_pktsnip_t *netif;
ng_netif_hdr_t *netif_hdr = NULL;
DEBUG("ndp: received neighbor advertisement (src: %s, ",
ng_ipv6_addr_to_str(addr_str, &ipv6->src, sizeof(addr_str)));
DEBUG("dst: %s, ",
ng_ipv6_addr_to_str(addr_str, &ipv6->dst, sizeof(addr_str)));
DEBUG("tgt: %s)\n",
ng_ipv6_addr_to_str(addr_str, &nbr_adv->tgt, sizeof(addr_str)));
/* check validity */
if ((ipv6->hl != 255) || (nbr_adv->code != 0) ||
(icmpv6_size < sizeof(ng_ndp_nbr_adv_t)) ||
ng_ipv6_addr_is_multicast(&nbr_adv->tgt)) {
DEBUG("ndp: neighbor advertisement was invalid.\n");
/* ipv6 releases */
return;
}
if (nc_entry == NULL) {
/* see https://tools.ietf.org/html/rfc4861#section-7.2.5 */
DEBUG("ndp: no neighbor cache entry found for advertisement's target\n");
/* ipv6 releases */
return;
}
sicmpv6_size -= sizeof(ng_ndp_nbr_adv_t);
while (sicmpv6_size > 0) {
ng_ndp_opt_t *opt = (ng_ndp_opt_t *)(buf + opt_offset);
switch (opt->type) {
case NG_NDP_OPT_TL2A:
if ((l2tgt_len = _handle_tl2a_opt(pkt, ipv6, nbr_adv->type, opt,
l2tgt)) < 0) {
/* invalid target link-layer address option */
return;
}
break;
default:
/* silently discard all other options */
break;
}
opt_offset += (opt->len * 8);
sicmpv6_size -= (opt->len * 8);
}
LL_SEARCH_SCALAR(pkt, netif, type, NG_NETTYPE_NETIF);
if (netif != NULL) {
netif_hdr = netif->data;
}
if (ng_ipv6_nc_get_state(nc_entry) == NG_IPV6_NC_STATE_INCOMPLETE) {
ng_pktqueue_t *queued_pkt;
if (_pkt_has_l2addr(netif_hdr) && (l2tgt_len == 0)) {
/* link-layer has addresses, but no TLLAO supplied: discard silently
* (see https://tools.ietf.org/html/rfc4861#section-7.2.5) */
return;
}
nc_entry->iface = iface;
nc_entry->l2_addr_len = l2tgt_len;
memcpy(nc_entry->l2_addr, l2tgt, l2tgt_len);
if (nbr_adv->flags & NG_NDP_NBR_ADV_FLAGS_S) {
_set_state(nc_entry, NG_IPV6_NC_STATE_REACHABLE);
}
else {
_set_state(nc_entry, NG_IPV6_NC_STATE_STALE);
}
if (nbr_adv->flags & NG_NDP_NBR_ADV_FLAGS_R) {
nc_entry->flags |= NG_IPV6_NC_IS_ROUTER;
}
else {
nc_entry->flags &= ~NG_IPV6_NC_IS_ROUTER;
/* TODO: update FIB */
}
while ((queued_pkt = ng_pktqueue_remove_head(&nc_entry->pkts)) != NULL) {
ng_netapi_send(ng_ipv6_pid, queued_pkt->pkt);
queued_pkt->pkt = NULL;
}
}
else {
/* first or-term: no link-layer, but nc_entry has l2addr,
* second or-term: different l2addr cached */
bool l2tgt_changed = false;
if ((!_pkt_has_l2addr(netif_hdr)) && (l2tgt_len == 0)) {
/* there was previously a L2 address registered */
l2tgt_changed = (nc_entry->l2_addr_len != 0);
}
/* link-layer has addresses and TLLAO with different address */
else if (_pkt_has_l2addr(netif_hdr) && (l2tgt_len != 0)) {
l2tgt_changed = (!(l2tgt_len == nc_entry->l2_addr_len)) &&
(memcmp(nc_entry->l2_addr, l2tgt, l2tgt_len) == 0);
}
if ((nbr_adv->flags & NG_NDP_NBR_ADV_FLAGS_O) || !l2tgt_changed ||
(l2tgt_len == 0)) {
if (l2tgt_len != 0) {
nc_entry->iface = iface;
nc_entry->l2_addr_len = l2tgt_len;
memcpy(nc_entry->l2_addr, l2tgt, l2tgt_len);
}
if (nbr_adv->flags & NG_NDP_NBR_ADV_FLAGS_S) {
_set_state(nc_entry, NG_IPV6_NC_STATE_REACHABLE);
}
else if (l2tgt_changed && (l2tgt_len != 0)) {
_set_state(nc_entry, NG_IPV6_NC_STATE_STALE);
}
if (nbr_adv->flags & NG_NDP_NBR_ADV_FLAGS_R) {
nc_entry->flags |= NG_IPV6_NC_IS_ROUTER;
}
else {
nc_entry->flags &= ~NG_IPV6_NC_IS_ROUTER;
/* TODO: update FIB */
}
}
else if (l2tgt_changed) {
if (ng_ipv6_nc_get_state(nc_entry) == NG_IPV6_NC_STATE_REACHABLE) {
_set_state(nc_entry, NG_IPV6_NC_STATE_STALE);
}
}
}
return;
}
void ng_ndp_retrans_nbr_sol(ng_ipv6_nc_t *nc_entry)
{
if ((ng_ipv6_nc_get_state(nc_entry) == NG_IPV6_NC_STATE_INCOMPLETE) ||
(ng_ipv6_nc_get_state(nc_entry) == NG_IPV6_NC_STATE_PROBE)) {
if (nc_entry->probes_remaining > 1) {
ng_ipv6_addr_t dst;
DEBUG("ndp: Retransmit neighbor solicitation for %s\n",
ng_ipv6_addr_to_str(addr_str, &nc_entry->ipv6_addr, sizeof(addr_str)));
/* retransmit neighbor solicatation */
if (ng_ipv6_nc_get_state(nc_entry) == NG_IPV6_NC_STATE_INCOMPLETE) {
ng_ipv6_addr_set_solicited_nodes(&dst, &nc_entry->ipv6_addr);
}
else {
dst.u64[0] = nc_entry->ipv6_addr.u64[0];
dst.u64[1] = nc_entry->ipv6_addr.u64[1];
}
nc_entry->probes_remaining--;
if (nc_entry->iface == KERNEL_PID_UNDEF) {
timex_t t = { 0, NG_NDP_RETRANS_TIMER };
kernel_pid_t ifs[NG_NETIF_NUMOF];
size_t ifnum = ng_netif_get(ifs);
for (size_t i = 0; i < ifnum; i++) {
_send_nbr_sol(ifs[i], &nc_entry->ipv6_addr, &dst);
}
vtimer_remove(&nc_entry->nbr_sol_timer);
vtimer_set_msg(&nc_entry->nbr_sol_timer, t, ng_ipv6_pid,
NG_NDP_MSG_NBR_SOL_RETRANS, nc_entry);
}
else {
ng_ipv6_netif_t *ipv6_iface = ng_ipv6_netif_get(nc_entry->iface);
_send_nbr_sol(nc_entry->iface, &nc_entry->ipv6_addr, &dst);
mutex_lock(&ipv6_iface->mutex);
vtimer_remove(&nc_entry->nbr_sol_timer);
vtimer_set_msg(&nc_entry->nbr_sol_timer,
ipv6_iface->retrans_timer, ng_ipv6_pid,
NG_NDP_MSG_NBR_SOL_RETRANS, nc_entry);
mutex_unlock(&ipv6_iface->mutex);
}
}
else if (nc_entry->probes_remaining <= 1) {
DEBUG("ndp: Remove nc entry %s for interface %" PRIkernel_pid "\n",
ng_ipv6_addr_to_str(addr_str, &nc_entry->ipv6_addr, sizeof(addr_str)),
nc_entry->iface);
#ifdef MODULE_FIB
fib_remove_entry((uint8_t *) & (nc_entry->ipv6_addr), sizeof(ng_ipv6_addr_t));
#endif
ng_ipv6_nc_remove(nc_entry->iface, &nc_entry->ipv6_addr);
}
}
}
void ng_ndp_state_timeout(ng_ipv6_nc_t *nc_entry)
{
switch (ng_ipv6_nc_get_state(nc_entry)) {
case NG_IPV6_NC_STATE_REACHABLE:
_set_state(nc_entry, NG_IPV6_NC_STATE_STALE);
break;
case NG_IPV6_NC_STATE_DELAY:
_set_state(nc_entry, NG_IPV6_NC_STATE_PROBE);
break;
default:
break;
}
}
void ng_ndp_netif_add(ng_ipv6_netif_t *iface)
{
uint32_t reach_time = _rand(NG_NDP_MIN_RAND, NG_NDP_MAX_RAND);
/* set default values */
mutex_lock(&iface->mutex);
iface->reach_time_base = NG_NDP_REACH_TIME;
reach_time = (reach_time * iface->reach_time_base) / 10;
iface->reach_time = timex_set(0, reach_time);
timex_normalize(&iface->reach_time);
iface->retrans_timer = timex_set(0, NG_NDP_RETRANS_TIMER);
timex_normalize(&iface->retrans_timer);
mutex_unlock(&iface->mutex);
}
void ng_ndp_netif_remove(ng_ipv6_netif_t *iface)
{
/* TODO */
(void) iface;
}
static ng_ipv6_addr_t *_default_router(void)
{
ng_ipv6_nc_t *router = ng_ipv6_nc_get_next_router(NULL);
/* first look if there is any reachable router */
while (router != NULL) {
if ((ng_ipv6_nc_get_state(router) != NG_IPV6_NC_STATE_INCOMPLETE) &&
(ng_ipv6_nc_get_state(router) != NG_IPV6_NC_STATE_UNREACHABLE)) {
_last_router = NULL;
return &router->ipv6_addr;
}
router = ng_ipv6_nc_get_next_router(router);
}
/* else take the first one, but keep round-robin in further selections */
router = ng_ipv6_nc_get_next_router(_last_router);
if (router == NULL) { /* end of router list or there is none => wrap around */
router = ng_ipv6_nc_get_next_router(router);
if (router == NULL) { /* still nothing found => no router in list */
return NULL;
}
}
_last_router = router;
return &router->ipv6_addr;
}
kernel_pid_t ng_ndp_next_hop_l2addr(uint8_t *l2addr, uint8_t *l2addr_len,
kernel_pid_t iface, ng_ipv6_addr_t *dst,
ng_pktsnip_t *pkt)
{
ng_ipv6_addr_t *next_hop_ip = NULL, *prefix = NULL;
#ifdef MODULE_NG_IPV6_EXT_RH
next_hop_ip = ng_ipv6_ext_rh_next_hop(hdr);
#endif
#ifdef MODULE_FIB
size_t next_hop_size;
uint32_t next_hop_flags = 0;
ng_ipv6_addr_t next_hop_actual; /* FIB copies address into this variable */
if ((next_hop_ip == NULL) &&
(fib_get_next_hop(&iface, next_hop_actual.u8, &next_hop_size,
&next_hop_flags, (uint8_t *)dst,
sizeof(ng_ipv6_addr_t), 0) >= 0) &&
(next_hop_size == sizeof(ng_ipv6_addr_t))) {
next_hop_ip = &next_hop_actual;
}
#endif
if ((next_hop_ip == NULL)) { /* no route to host */
if (iface == KERNEL_PID_UNDEF) {
/* ng_ipv6_netif_t doubles as prefix list */
iface = ng_ipv6_netif_find_by_prefix(&prefix, dst);
}
else {
/* ng_ipv6_netif_t doubles as prefix list */
prefix = ng_ipv6_netif_match_prefix(iface, dst);
}
if ((prefix != NULL) && /* prefix is on-link */
(ng_ipv6_netif_addr_get(prefix)->flags &
NG_IPV6_NETIF_ADDR_FLAGS_NDP_ON_LINK)) {
next_hop_ip = dst;
#ifdef MODULE_FIB
/* We don't care if FIB is full, this is just for efficiency
* for later sends */
fib_add_entry(iface, (uint8_t *)dst, sizeof(ng_ipv6_addr_t), 0,
(uint8_t *)next_hop_ip, sizeof(ng_ipv6_addr_t), 0,
FIB_LIFETIME_NO_EXPIRE);
#endif
}
}
if (next_hop_ip == NULL) {
next_hop_ip = _default_router();
#ifdef MODULE_FIB
/* We don't care if FIB is full, this is just for efficiency for later
* sends */
fib_add_entry(iface, (uint8_t *)dst, sizeof(ng_ipv6_addr_t), 0,
(uint8_t *)next_hop_ip, sizeof(ng_ipv6_addr_t), 0,
FIB_LIFETIME_NO_EXPIRE);
#endif
}
if (next_hop_ip != NULL) {
ng_ipv6_nc_t *nc_entry = ng_ipv6_nc_get(iface, next_hop_ip);
if ((nc_entry != NULL) && ng_ipv6_nc_is_reachable(nc_entry)) {
DEBUG("ndp: found reachable neighbor (%s => ",
ng_ipv6_addr_to_str(addr_str, &nc_entry->ipv6_addr, sizeof(addr_str)));
DEBUG("%s)\n",
ng_netif_addr_to_str(addr_str, sizeof(addr_str),
nc_entry->l2_addr, nc_entry->l2_addr_len));
if (ng_ipv6_nc_get_state(nc_entry) == NG_IPV6_NC_STATE_STALE) {
_set_state(nc_entry, NG_IPV6_NC_STATE_DELAY);
}
memcpy(l2addr, nc_entry->l2_addr, nc_entry->l2_addr_len);
*l2addr_len = nc_entry->l2_addr_len;
/* TODO: unreachability check */
return nc_entry->iface;
}
else if (nc_entry == NULL) {
ng_pktqueue_t *pkt_node;
ng_ipv6_addr_t dst_sol;
nc_entry = ng_ipv6_nc_add(iface, next_hop_ip, NULL, 0,
NG_IPV6_NC_STATE_INCOMPLETE << NG_IPV6_NC_STATE_POS);
if (nc_entry == NULL) {
DEBUG("ndp: could not create neighbor cache entry\n");
return KERNEL_PID_UNDEF;
}
pkt_node = _alloc_pkt_node(pkt);
if (pkt_node == NULL) {
DEBUG("ndp: could not add packet to packet queue\n");
}
else {
/* prevent packet from being released by IPv6 */
ng_pktbuf_hold(pkt_node->pkt, 1);
ng_pktqueue_add(&nc_entry->pkts, pkt_node);
}
/* address resolution */
ng_ipv6_addr_set_solicited_nodes(&dst_sol, next_hop_ip);
if (iface == KERNEL_PID_UNDEF) {
timex_t t = { 0, NG_NDP_RETRANS_TIMER };
kernel_pid_t ifs[NG_NETIF_NUMOF];
size_t ifnum = ng_netif_get(ifs);
for (size_t i = 0; i < ifnum; i++) {
_send_nbr_sol(ifs[i], next_hop_ip, &dst_sol);
}
vtimer_remove(&nc_entry->nbr_sol_timer);
vtimer_set_msg(&nc_entry->nbr_sol_timer, t, ng_ipv6_pid,
NG_NDP_MSG_NBR_SOL_RETRANS, nc_entry);
}
else {
ng_ipv6_netif_t *ipv6_iface = ng_ipv6_netif_get(iface);
_send_nbr_sol(iface, next_hop_ip, &dst_sol);
mutex_lock(&ipv6_iface->mutex);
vtimer_remove(&nc_entry->nbr_sol_timer);
vtimer_set_msg(&nc_entry->nbr_sol_timer,
ipv6_iface->retrans_timer, ng_ipv6_pid,
NG_NDP_MSG_NBR_SOL_RETRANS, nc_entry);
mutex_unlock(&ipv6_iface->mutex);
}
}
}
return KERNEL_PID_UNDEF;
}
ng_pktsnip_t *ng_ndp_nbr_sol_build(ng_ipv6_addr_t *tgt, ng_pktsnip_t *options)
{
ng_pktsnip_t *pkt;
DEBUG("ndp: building neighbor solicitation message\n");
if (ng_ipv6_addr_is_multicast(tgt)) {
DEBUG("ndp: tgt must not be multicast\n");
return NULL;
}
pkt = ng_icmpv6_build(options, NG_ICMPV6_NBR_SOL, 0, sizeof(ng_ndp_nbr_sol_t));
if (pkt != NULL) {
ng_ndp_nbr_sol_t *nbr_sol = pkt->data;
nbr_sol->resv.u32 = 0;
nbr_sol->tgt.u64[0].u64 = tgt->u64[0].u64;
nbr_sol->tgt.u64[1].u64 = tgt->u64[1].u64;
}
return pkt;
}
ng_pktsnip_t *ng_ndp_nbr_adv_build(uint8_t flags, ng_ipv6_addr_t *tgt,
ng_pktsnip_t *options)
{
ng_pktsnip_t *pkt;
DEBUG("ndp: building neighbor advertisement message\n");
if (ng_ipv6_addr_is_multicast(tgt)) {
DEBUG("ndp: tgt must not be multicast\n");
return NULL;
}
pkt = ng_icmpv6_build(options, NG_ICMPV6_NBR_ADV, 0, sizeof(ng_ndp_nbr_adv_t));
if (pkt != NULL) {
ng_ndp_nbr_adv_t *nbr_adv = pkt->data;
nbr_adv->flags = (flags & NG_NDP_NBR_ADV_FLAGS_MASK);
nbr_adv->resv[0] = nbr_adv->resv[1] = nbr_adv->resv[2] = 0;
nbr_adv->tgt.u64[0].u64 = tgt->u64[0].u64;
nbr_adv->tgt.u64[1].u64 = tgt->u64[1].u64;
}
return pkt;
}
static inline size_t _ceil8(uint8_t length)
{
/* NDP options use units of 8 byte for there length field, so round up */
return (length + 7U) & 0xf8U;
}
ng_pktsnip_t *ng_ndp_opt_build(uint8_t type, size_t size, ng_pktsnip_t *next)
{
ng_ndp_opt_t *opt;
ng_pktsnip_t *pkt = ng_pktbuf_add(next, NULL, _ceil8(size), NG_NETTYPE_UNDEF);
if (pkt == NULL) {
DEBUG("ndp: no space left in packet buffer\n");
return NULL;
}
opt = pkt->data;
opt->type = type;
opt->len = (uint8_t)(pkt->size / 8);
return pkt;
}
static uint16_t _get_l2src(uint8_t *l2src, size_t l2src_size, kernel_pid_t iface)
{
bool try_long = false;
int res;
uint16_t l2src_len;
/* maximum address length that fits into a minimum length (8) S/TL2A option */
const uint16_t max_short_len = 6;
/* try getting source address */
if ((ng_netapi_get(iface, NETCONF_OPT_SRC_LEN, 0, &l2src_len,
sizeof(l2src_len)) >= 0) &&
(l2src_len > max_short_len)) {
try_long = true;
}
if (try_long && ((res = ng_netapi_get(iface, NETCONF_OPT_ADDRESS_LONG, 0,
l2src, l2src_size)) > max_short_len)) {
l2src_len = (uint16_t)res;
}
else if ((res = ng_netapi_get(iface, NETCONF_OPT_ADDRESS, 0, l2src,
l2src_size)) >= 0) {
l2src_len = (uint16_t)res;
}
else {
DEBUG("ndp: no link-layer address found.\n");
l2src_len = 0;
}
return l2src_len;
}
static void _send_nbr_sol(kernel_pid_t iface, ng_ipv6_addr_t *tgt,
ng_ipv6_addr_t *dst)
{
ng_pktsnip_t *hdr, *pkt = NULL;
ng_ipv6_addr_t *src = NULL;
size_t src_len = 0;
DEBUG("ndp: send neighbor solicitation (iface: %" PRIkernel_pid ", tgt: %s, ",
iface, ng_ipv6_addr_to_str(addr_str, tgt, sizeof(addr_str)));
DEBUG("dst: %s)\n", ng_ipv6_addr_to_str(addr_str, dst, sizeof(addr_str)));
/* check if there is a fitting source address to target */
if ((src = ng_ipv6_netif_find_best_src_addr(iface, tgt)) != NULL) {
uint8_t l2src[8];
uint16_t l2src_len;
src_len = sizeof(ng_ipv6_addr_t);
l2src_len = _get_l2src(l2src, sizeof(l2src), iface);
if (l2src_len > 0) {
/* add source address link-layer address option */
pkt = ng_ndp_opt_sl2a_build(l2src, l2src_len, NULL);
if (pkt == NULL) {
DEBUG("ndp: error allocating Source Link-layer address option.\n");
ng_pktbuf_release(pkt);
return;
}
}
}
hdr = ng_ndp_nbr_sol_build(tgt, pkt);
if (hdr == NULL) {
DEBUG("ndp: error allocating Neighbor solicitation.\n");
ng_pktbuf_release(pkt);
return;
}
pkt = hdr;
hdr = ng_ipv6_hdr_build(pkt, (uint8_t *)src, src_len, (uint8_t *)dst,
sizeof(ng_ipv6_addr_t));
if (hdr == NULL) {
DEBUG("ndp: error allocating IPv6 header.\n");
ng_pktbuf_release(pkt);
return;
}
((ng_ipv6_hdr_t *)hdr->data)->hl = 255;
pkt = hdr;
/* add netif header for send interface specification */
hdr = ng_netif_hdr_build(NULL, 0, NULL, 0);
if (hdr == NULL) {
DEBUG("ndp: error allocating netif header.\n");
return;
}
((ng_netif_hdr_t *)hdr->data)->if_pid = iface;
LL_PREPEND(pkt, hdr);
ng_netapi_send(ng_ipv6_pid, pkt);
}
static void _send_nbr_adv(kernel_pid_t iface, ng_ipv6_addr_t *tgt,
ng_ipv6_addr_t *dst, bool supply_tl2a)
{
ng_pktsnip_t *hdr, *pkt = NULL;
uint8_t adv_flags = 0;
DEBUG("ndp: send neighbor advertisement (iface: %" PRIkernel_pid ", tgt: %s, ",
iface, ng_ipv6_addr_to_str(addr_str, tgt, sizeof(addr_str)));
DEBUG("dst: %s, supply_tl2a: %d)\n",
ng_ipv6_addr_to_str(addr_str, dst, sizeof(addr_str)), supply_tl2a);
if (ng_ipv6_netif_get(iface)->flags & NG_IPV6_NETIF_FLAGS_ROUTER) {
adv_flags |= NG_NDP_NBR_ADV_FLAGS_R;
}
if (ng_ipv6_addr_is_unspecified(dst)) {
ng_ipv6_addr_set_all_nodes_multicast(dst,
NG_IPV6_ADDR_MCAST_SCP_LINK_LOCAL);
}
else {
adv_flags |= NG_NDP_NBR_ADV_FLAGS_S;
}
if (supply_tl2a) {
uint8_t l2src[8];
uint16_t l2src_len;
/* we previously checked if we are the target, so we can take our L2src */
l2src_len = _get_l2src(l2src, sizeof(l2src), iface);
if (l2src_len > 0) {
/* add target address link-layer address option */
pkt = ng_ndp_opt_tl2a_build(l2src, l2src_len, NULL);
if (pkt == NULL) {
DEBUG("ndp: error allocating Target Link-layer address option.\n");
ng_pktbuf_release(pkt);
return;
}
}
}
/* TODO: also check if the node provides proxy servies for tgt */
if ((pkt != NULL) && !ng_ipv6_netif_addr_is_non_unicast(tgt)) {
/* TL2A is not supplied and tgt is not anycast */
adv_flags |= NG_NDP_NBR_ADV_FLAGS_O;
}
hdr = ng_ndp_nbr_adv_build(adv_flags, tgt, pkt);
if (hdr == NULL) {
DEBUG("ndp: error allocating Neighbor advertisement.\n");
ng_pktbuf_release(pkt);
return;
}
pkt = hdr;
hdr = ng_ipv6_hdr_build(pkt, NULL, 0, (uint8_t *)dst,
sizeof(ng_ipv6_addr_t));
if (hdr == NULL) {
DEBUG("ndp: error allocating IPv6 header.\n");
ng_pktbuf_release(pkt);
return;
}
((ng_ipv6_hdr_t *)hdr->data)->hl = 255;
pkt = hdr;
/* add netif header for send interface specification */
hdr = ng_netif_hdr_build(NULL, 0, NULL, 0);
if (hdr == NULL) {
DEBUG("ndp: error allocating netif header.\n");
return;
}
((ng_netif_hdr_t *)hdr->data)->if_pid = iface;
LL_PREPEND(pkt, hdr);
if (ng_ipv6_netif_addr_is_non_unicast(tgt)) {
/* avoid collision for anycast addresses
* (see https://tools.ietf.org/html/rfc4861#section-7.2.7) */
timex_t delay = { _rand(0, NG_NDP_MAX_AC_TGT_DELAY), 0 };
ng_ipv6_nc_t *nc_entry = ng_ipv6_nc_get(iface, tgt);
DEBUG("ndp: delay neighbor advertisement for %" PRIu32 " sec.",
delay.seconds);
/* nc_entry must be set so no need to check it */
_send_delayed(&nc_entry->nbr_adv_timer, delay, pkt);
}
else {
ng_netapi_send(ng_ipv6_pid, pkt);
}
}
static inline ng_pktsnip_t *_opt_l2a_build(uint8_t type, const uint8_t *l2addr,
uint8_t l2addr_len, ng_pktsnip_t *next)
{
ng_pktsnip_t *pkt = ng_ndp_opt_build(type, sizeof(ng_ndp_opt_t) + l2addr_len,
next);
if (pkt != NULL) {
ng_ndp_opt_t *l2a_opt = pkt->data;
memset(l2a_opt + 1, 0, pkt->size - sizeof(ng_ndp_opt_t));
memcpy(l2a_opt + 1, l2addr, l2addr_len);
}
return pkt;
}
ng_pktsnip_t *ng_ndp_opt_sl2a_build(const uint8_t *l2addr, uint8_t l2addr_len,
ng_pktsnip_t *next)
{
DEBUG("ndp: building source link-layer address option (l2addr: %s)\n",
ng_netif_addr_to_str(addr_str, sizeof(addr_str), l2addr, l2addr_len));
return _opt_l2a_build(NG_NDP_OPT_SL2A, l2addr, l2addr_len, next);
}
ng_pktsnip_t *ng_ndp_opt_tl2a_build(const uint8_t *l2addr, uint8_t l2addr_len,
ng_pktsnip_t *next)
{
DEBUG("ndp: building target link-layer address option (l2addr: %s)\n",
ng_netif_addr_to_str(addr_str, sizeof(addr_str), l2addr, l2addr_len));
return _opt_l2a_build(NG_NDP_OPT_TL2A, l2addr, l2addr_len, next);
}
/* internal functions */
/* packet queue node allocation */
static ng_pktqueue_t *_alloc_pkt_node(ng_pktsnip_t *pkt)
{
for (size_t i = 0; i < sizeof(_pkt_nodes) / sizeof(ng_pktqueue_t); i++) {
if ((_pkt_nodes[i].pkt == NULL) && (_pkt_nodes[i].next == NULL)) {
_pkt_nodes[i].pkt = pkt;
return &(_pkt_nodes[i]);
}
}
return NULL;
}
static bool _handle_sl2a_opt(kernel_pid_t iface, ng_pktsnip_t *pkt,
ng_ipv6_hdr_t *ipv6, uint8_t icmpv6_type,
ng_ndp_opt_t *sl2a_opt)
{
ng_ipv6_nc_t *nc_entry = NULL;
uint8_t sl2a_len = 0;
uint8_t *sl2a = (uint8_t *)(sl2a_opt + 1);
if ((sl2a_opt->len == 0) || ng_ipv6_addr_is_unspecified(&ipv6->src)) {
DEBUG("ndp: invalid source link-layer address option received\n");
return false;
}
while (pkt) {
if (pkt->type == NG_NETTYPE_NETIF) {
ng_netif_hdr_t *hdr = pkt->data;
sl2a_len = hdr->src_l2addr_len;
break;
}
pkt = pkt->next;
}
if (sl2a_len == 0) { /* in case there was no source address in l2 */
sl2a_len = (sl2a_opt->len / 8) - sizeof(ng_ndp_opt_t);
/* ignore all zeroes at the end for length */
for (; sl2a[sl2a_len - 1] == 0x00; sl2a_len--);
}
DEBUG("ndp: received SL2A (link-layer address: %s)\n",
ng_netif_addr_to_str(addr_str, sizeof(addr_str), sl2a, sl2a_len));
switch (icmpv6_type) {
case NG_ICMPV6_NBR_SOL:
nc_entry = ng_ipv6_nc_get(iface, &ipv6->src);
if (nc_entry != NULL) {
if ((sl2a_len != nc_entry->l2_addr_len) ||
(memcmp(sl2a, nc_entry->l2_addr, sl2a_len) != 0)) {
/* if entry exists but l2 address differs: set */
nc_entry->l2_addr_len = sl2a_len;
memcpy(nc_entry->l2_addr, sl2a, sl2a_len);
_set_state(nc_entry, NG_IPV6_NC_STATE_STALE);
}
}
else {
ng_ipv6_nc_add(iface, &ipv6->src, sl2a, sl2a_len,
NG_IPV6_NC_STATE_STALE);
}
return true;
default: /* wrong encapsulating message: silently discard */
DEBUG("ndp: silently discard sl2a_opt for ICMPv6 message type %"
PRIu8 "\n", icmpv6_type);
return true;
}
}
static int _handle_tl2a_opt(ng_pktsnip_t *pkt, ng_ipv6_hdr_t *ipv6,
uint8_t icmpv6_type, ng_ndp_opt_t *tl2a_opt,
uint8_t *l2addr)
{
uint8_t tl2a_len = 0;
uint8_t *tl2a = (uint8_t *)(tl2a_opt + 1);
if ((tl2a_opt->len == 0) || ng_ipv6_addr_is_unspecified(&ipv6->src)) {
DEBUG("ndp: invalid target link-layer address option received\n");
return -EINVAL;
}
switch (icmpv6_type) {
case NG_ICMPV6_NBR_ADV:
while (pkt) {
if (pkt->type == NG_NETTYPE_NETIF) {
ng_netif_hdr_t *hdr = pkt->data;
tl2a_len = hdr->src_l2addr_len;
break;
}
pkt = pkt->next;
}
if (tl2a_len == 0) { /* in case there was no source address in l2 */
tl2a_len = (tl2a_opt->len / 8) - sizeof(ng_ndp_opt_t);
/* ignore all zeroes at the end for length */
for (; tl2a[tl2a_len - 1] == 0x00; tl2a_len--);
}
DEBUG("ndp: received TL2A (link-layer address: %s)\n",
ng_netif_addr_to_str(addr_str, sizeof(addr_str), tl2a, tl2a_len));
memcpy(l2addr, tl2a, tl2a_len);
return (int)tl2a_len;
default: /* wrong encapsulating message: silently discard */
DEBUG("ndp: silently discard tl2a_opt for ICMPv6 message type %"
PRIu8 "\n", icmpv6_type);
return 0;
}
}
static void _set_state(ng_ipv6_nc_t *nc_entry, uint8_t state)
{
ng_ipv6_netif_t *ipv6_iface;
timex_t t = { NG_NDP_FIRST_PROBE_DELAY, 0 };
nc_entry->flags &= ~NG_IPV6_NC_STATE_MASK;
nc_entry->flags |= state;
DEBUG("ndp: set %s state to ",
ng_ipv6_addr_to_str(addr_str, &nc_entry->ipv6_addr, sizeof(addr_str)));
switch (state) {
case NG_IPV6_NC_STATE_REACHABLE:
ipv6_iface = ng_ipv6_netif_get(nc_entry->iface);
DEBUG("REACHABLE (reachable time = %" PRIu32 ".%06" PRIu32 ")\n",
ipv6_iface->reach_time.seconds,
ipv6_iface->reach_time.microseconds);
t = ipv6_iface->reach_time;
/* we intentionally fall through here to set the desired timeout t */
case NG_IPV6_NC_STATE_DELAY:
#if ENABLE_DEBUG
if (state == NG_IPV6_NC_STATE_DELAY) {
DEBUG("DELAY (probe with unicast NS in %u seconds)\n",
NG_NDP_FIRST_PROBE_DELAY);
}
#endif
vtimer_remove(&nc_entry->nbr_sol_timer);
vtimer_set_msg(&nc_entry->nbr_sol_timer, t, ng_ipv6_pid,
NG_NDP_MSG_NC_STATE_TIMEOUT, nc_entry);
break;
case NG_IPV6_NC_STATE_PROBE:
ipv6_iface = ng_ipv6_netif_get(nc_entry->iface);
nc_entry->probes_remaining = NG_NDP_MAX_UC_NBR_SOL_NUMOF;
DEBUG("PROBE (probe with %" PRIu8 " unicast NS every %" PRIu32
".%06" PRIu32 " seconds)\n", nc_entry->probes_remaining,
ipv6_iface->retrans_timer.seconds,
ipv6_iface->retrans_timer.microseconds);
_send_nbr_sol(nc_entry->iface, &nc_entry->ipv6_addr,
&nc_entry->ipv6_addr);
mutex_lock(&ipv6_iface->mutex);
vtimer_remove(&nc_entry->nbr_sol_timer);
vtimer_set_msg(&nc_entry->nbr_sol_timer,
ipv6_iface->retrans_timer, ng_ipv6_pid,
NG_NDP_MSG_NBR_SOL_RETRANS, nc_entry);
mutex_unlock(&ipv6_iface->mutex);
break;
#ifdef ENABLE_DEBUG
case NG_IPV6_NC_STATE_STALE:
DEBUG("STALE (go into DELAY on next packet)\n");
break;
#endif
default:
DEBUG("errorneous or unknown\n");
break;
}
}
/**
* @}
*/
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