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ng_ndp: fix neighbor advertisement handling

Browse Source 
The setting of the states and reset of the retransmission timers is
broken in the current implementation. This patch fixes that behavior and
simplifies the code a little.
This commit is contained in:
Martine Lenders 2015-06-09 18:07:19 +02:00
parent 70abb0c4ed
commit f0134f613c
1 changed files with 120 additions and 102 deletions
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222
sys/net/network_layer/ng_ndp/ng_ndp.c
View File

@ -15,6 +15,7 @@
* @author Martine Lenders <mlenders@inf.fu-berlin.de>
*/
#include <errno.h>
#include <string.h>
#include "byteorder.h"
@ -52,10 +53,9 @@ static inline uint32_t _rand(uint32_t min, uint32_t max)
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 bool _handle_tl2a_opt(kernel_pid_t iface, ng_pktsnip_t *pkt,
ng_ipv6_hdr_t *ipv6, uint8_t icmpv6_type,
ng_ndp_opt_t *tl2a_opt, ng_ipv6_addr_t *tgt,
uint8_t adv_flags);
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,
@ -130,14 +130,24 @@ void ng_ndp_nbr_sol_handle(kernel_pid_t iface, ng_pktsnip_t *pkt,
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);
bool tl2a_supplied = false;
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;
/* check validity */
if ((ipv6->hl != 255) || (nbr_adv->code != 0) ||
@ -148,13 +158,13 @@ void ng_ndp_nbr_adv_handle(kernel_pid_t iface, ng_pktsnip_t *pkt,
return;
}
if (ng_ipv6_nc_get(iface, &nbr_adv->tgt) == NULL) {
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) {
@ -162,14 +172,12 @@ void ng_ndp_nbr_adv_handle(kernel_pid_t iface, ng_pktsnip_t *pkt,
switch (opt->type) {
case NG_NDP_OPT_TL2A:
if (!_handle_tl2a_opt(iface, pkt, ipv6, nbr_adv->type, opt,
&nbr_adv->tgt, nbr_adv->flags)) {
if ((l2tgt_len = _handle_tl2a_opt(pkt, ipv6, nbr_adv->type, opt,
l2tgt)) < 0) {
/* invalid target link-layer address option */
return;
}
tl2a_supplied = true;
break;
default:
@ -181,17 +189,87 @@ void ng_ndp_nbr_adv_handle(kernel_pid_t iface, ng_pktsnip_t *pkt,
sicmpv6_size -= (opt->len * 8);
}
if (!tl2a_supplied) {
if (nbr_adv->flags & NG_NDP_NBR_ADV_FLAGS_O) {
ng_ipv6_nc_t *nc_entry = ng_ipv6_nc_get(iface, &nbr_adv->tgt);
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_node_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->data);
queued_pkt->data = 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);
if (nc_entry != NULL) {
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);
}
}
}
}
@ -803,104 +881,44 @@ static bool _handle_sl2a_opt(kernel_pid_t iface, ng_pktsnip_t *pkt,
}
}
static bool _handle_tl2a_opt(kernel_pid_t iface, ng_pktsnip_t *pkt,
ng_ipv6_hdr_t *ipv6, uint8_t icmpv6_type,
ng_ndp_opt_t *tl2a_opt, ng_ipv6_addr_t *tgt,
uint8_t adv_flags)
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)
{
ng_ipv6_nc_t *nc_entry = NULL;
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 false;
}
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--);
return -EINVAL;
}
switch (icmpv6_type) {
case NG_ICMPV6_NBR_ADV:
nc_entry = ng_ipv6_nc_get(iface, tgt);
/* no need to create an entry in the negative case (see RFC 4861) */
if (nc_entry != NULL) {
nc_entry->l2_addr_len = tl2a_len;
if (tl2a_len > 0) {
memcpy(nc_entry->l2_addr, tl2a, tl2a_len);
}
if (ng_ipv6_nc_get_state(nc_entry) == NG_IPV6_NC_STATE_INCOMPLETE) {
ng_pktqueue_node_t *queued_pkt;
if (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 (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;
}
while ((queued_pkt = ng_pktqueue_remove_head(&nc_entry->pkts)) != NULL) {
ng_netapi_send(ng_ipv6_pid, queued_pkt->data);
queued_pkt->data = NULL;
}
}
else {
if (memcmp(tl2a, nc_entry->l2_addr, tl2a_len) != 0) {
if ((adv_flags & NG_NDP_NBR_ADV_FLAGS_O)) {
memcpy(nc_entry->l2_addr, tl2a, tl2a_len);
}
else if (ng_ipv6_nc_get_state(nc_entry) == NG_IPV6_NC_STATE_REACHABLE) {
_set_state(nc_entry, NG_IPV6_NC_STATE_STALE);
}
}
if ((adv_flags & NG_NDP_NBR_ADV_FLAGS_O)) {
if (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 (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;
}
}
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;
}
return true;
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--);
}
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 true;
return 0;
}
}