/**
* @brief selects potential source address candidates
* @see <a href="http://tools.ietf.org/html/rfc6724#section-4">
* RFC6724, section 4
* </a>
* @param[in] netif the interface used for sending
* @param[in] dst the destination address
* @param[in] ll_only only consider link-local addresses
* @param[out] candidate_set a bitfield representing all addresses
* configured to @p netif, potential candidates
* will be marked as 1
*
* @return -1 if no candidates were found
* @return the index of the first candidate otherwise
*
* @pre the interface entry and its set of addresses must not be changed during
* runtime of this function
*/
static int _create_candidate_set(const gnrc_netif_t *netif,
const ipv6_addr_t *dst, bool ll_only,
uint8_t *candidate_set)
{
int res = -1;
DEBUG("gathering candidates\n");
/* currently this implementation supports only addresses as source address
* candidates assigned to this interface. Thus we assume all addresses to be
* on interface @p netif */
(void) dst;
for (int i = 0; i < GNRC_NETIF_IPV6_ADDRS_NUMOF; i++) {
const ipv6_addr_t *tmp = &(netif->ipv6.addrs[i]);
DEBUG("Checking address: %s\n",
ipv6_addr_to_str(addr_str, tmp, sizeof(addr_str)));
/* "In any case, multicast addresses and the unspecified address MUST NOT
* be included in a candidate set."
*/
if ((netif->ipv6.addrs_flags[i] == 0) ||
(gnrc_netif_ipv6_addr_get_state(netif, i) ==
GNRC_NETIF_IPV6_ADDRS_FLAGS_STATE_TENTATIVE)) {
continue;
}
/* Check if we only want link local addresses */
if (ll_only && !ipv6_addr_is_link_local(tmp)) {
continue;
}
/* "For all multicast and link-local destination addresses, the set of
* candidate source addresses MUST only include addresses assigned to
* interfaces belonging to the same link as the outgoing interface."
*
* "For site-local unicast destination addresses, the set of candidate
* source addresses MUST only include addresses assigned to interfaces
* belonging to the same site as the outgoing interface."
* -> we should also be fine, since we're only iterating addresses of
* the sending interface
*/
/* put all other addresses into the candidate set */
DEBUG("add to candidate set\n");
bf_set(candidate_set, i);
if (res < 0) {
res = i;
}
}
return res;
}
static inline bool _is_valid(const gnrc_netif_t *netif, int idx)
{
return (gnrc_netif_ipv6_addr_get_state(netif, idx) ==
GNRC_NETIF_IPV6_ADDRS_FLAGS_STATE_VALID);
}
static inline bool _is_tentative(const gnrc_netif_t *netif, int idx)
{
return (gnrc_netif_ipv6_addr_get_state(netif, idx) &
GNRC_NETIF_IPV6_ADDRS_FLAGS_STATE_TENTATIVE);
}
