bool rpl_data_remember_outer(buffer_t *buf)
{
/* We're stripping the IP header - need the HBH header for future reference */
uint8_t *hbh;
rpl_data_locate_info(buf, &hbh, NULL);
if (hbh) {
uint8_t instance_id = hbh[3];
/* For local instances, also need to extract the DODAG ID from src/dst */
bool local = rpl_instance_id_is_local(instance_id);
/* Copy the length byte and the option data (and optionally DODAG ID) */
buf->rpl_option = ns_dyn_mem_temporary_alloc(hbh[1] + 1 + (local ? 16 : 0));
if (buf->rpl_option) {
memcpy(buf->rpl_option, hbh + 1, hbh[1] + 1);
if (local) {
uint8_t *dodagid = instance_id & RPL_INSTANCE_DEST ? buf->dst_sa.address : buf->src_sa.address;
memcpy(buf->rpl_option + hbh[1] + 1, dodagid, 16);
}
}
}
if ((buf->options.ip_extflags & IPEXT_HBH_RPL) && !buf->rpl_option) {
tr_warn("RPL tunnel exit HbH fail");
return false;
}
return true;
}
uint8_t rpl_instance_list_read(uint8_t *buffer_ptr, uint8_t buffer_size)
{
uint8_t ret_val = 0;
struct rpl_instance *instance = NULL;
if (!protocol_6lowpan_rpl_domain) {
return 0;
}
while (buffer_size) {
instance = rpl_control_enumerate_instances(protocol_6lowpan_rpl_domain, instance);
if (!instance) {
break;
}
rpl_dodag_info_t dodag_info;
if (rpl_control_read_dodag_info(instance, &dodag_info)) {
/* First the instance ID */
*buffer_ptr++ = dodag_info.instance_id;
buffer_size--;
/* Then, if local, the DODAG ID */
if (rpl_instance_id_is_local(dodag_info.instance_id)) {
if (buffer_size < 16) {
break;
}
memcpy(buffer_ptr, dodag_info.dodag_id, 16);
buffer_ptr += 16;
buffer_size -= 16;
}
ret_val++;
}
}
return ret_val;
}
/*
* 0 1 2 3
* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | Option Type | Opt Data Len |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* |O|R|F|0|0|0|0|0| RPLInstanceID | SenderRank |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | (sub-TLVs) |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*
* Figure 1: RPL Option
*/
static buffer_t *rpl_data_exthdr_provider_hbh_2(buffer_t *buf, rpl_instance_t *instance, rpl_neighbour_t *neighbour, ipv6_exthdr_stage_t stage, int16_t *result)
{
ipv6_route_info_t *route_info = &buf->route->route_info;
/* This can be called both for routes which only use HbH headers (eg DIO)
* as well as one-hop DAO_SR routes which would normally use source routing
* headers, if there was more than one hop. For DAO_SR, neighbour will be
* NULL.
*/
rpl_dodag_t *dodag = rpl_instance_current_dodag(instance);
if (!dodag) {
*result = -1;
return buf;
}
bool destination_in_instance = false;
uint16_t ext_size = 0;
if (addr_ipv6_equal(route_info->next_hop_addr, buf->dst_sa.address) ||
addr_ipv6_equal(buf->dst_sa.address, dodag->id)) {
destination_in_instance = true;
if (buf->rpl_option) {
/* Forwarding an existing option - preserve it */
uint8_t opt_size = buf->rpl_option[0];
ext_size = 2 + opt_size;
ext_size = (ext_size + 7) &~ 7;
} else {
/* Generating our own option - fixed size, no TLVs */
ext_size = 8;
}
}
switch (stage) {
case IPV6_EXTHDR_SIZE:
*result = ext_size;
return buf;
case IPV6_EXTHDR_INSERT: {
if (!destination_in_instance) {
/* We don't add a header - we'll do it on the tunnel */
*result = 0;
return buf;
}
buf = buffer_headroom(buf, ext_size);
if (!buf) {
return NULL;
}
uint8_t *ext = buffer_data_reserve_header(buf, ext_size);
ext[0] = buf->options.type;
buf->options.type = IPV6_NH_HOP_BY_HOP;
ext[1] = ext_size / 8 - 1;
uint8_t *opt = ext + 2;
opt[0] = IPV6_OPTION_RPL;
if (buf->rpl_option) {
/* Get back the RPL option we stripped off an outer IP header */
memcpy(opt + 1, buf->rpl_option, 1 + buf->rpl_option[0]);
ns_dyn_mem_free(buf->rpl_option);
buf->rpl_option = NULL;
} else {
opt[1] = 4; // option length
opt[2] = 0; // placeholder
opt[3] = instance->id;
/* For upwards routes we can deduce that DODAGID must be
* the destination, so set the D flag.
*/
if (rpl_instance_id_is_local(instance->id) && !rpl_data_is_rpl_downward_route(route_info->source)) {
opt[3] |= RPL_INSTANCE_DEST;
}
common_write_16_bit(RPL_RANK_INFINITE, opt + 4); // SenderRank (placeholder)
}
/* Pad HbH header if necessary. */
uint8_t pad_len = ext + ext_size - (opt + 2 + opt[1]);
if (pad_len == 1) {
opt[0] = IPV6_OPTION_PAD1;
} else if (pad_len > 1) {
opt[0] = IPV6_OPTION_PADN;
opt[1] = pad_len - 2;
memset(opt + 2, 0, pad_len - 2);
}
// don't forget to set the "RPL option present" marker
buf->options.ip_extflags |= IPEXT_HBH_RPL;
*result = 0;
return buf;
}
case IPV6_EXTHDR_MODIFY: {
uint8_t *opt;
uint16_t sender_rank;
rpl_data_locate_info(buf, &opt, NULL);
if (!opt) {
*result = IPV6_EXTHDR_MODIFY_TUNNEL;
// Tunnel to next hop in general case, but if going to DODAGID,
// it can tunnel all the way (and it HAS to if it is a local
// DODAG).
if (!addr_ipv6_equal(buf->dst_sa.address, dodag->id)) {
memcpy(buf->dst_sa.address, route_info->next_hop_addr, 16);
}
buf->src_sa.addr_type = ADDR_NONE; // force auto-selection
return buf;
}
if (buf->ip_routed_up) {
/* Check for rank errors - RFC 6550 11.2.2.2. */
/* Note that RPL spec does not say that packets from nodes of
* equal rank are errors, but we treat them as such to get
* reliable sibling loop detection - we require sender rank to be
* strictly less for Down packets and strictly greater for Up.
*/
sender_rank = common_read_16_bit(opt + 4);
rpl_cmp_t cmp = rpl_rank_compare_dagrank_rank(dodag, sender_rank, instance->current_rank);
rpl_cmp_t expected_cmp = (opt[2] & RPL_OPT_DOWN) ? RPL_CMP_LESS : RPL_CMP_GREATER;
if (cmp != expected_cmp) {
/* Set the Rank-Error bit; if already set, drop */
if (opt[2] & RPL_OPT_RANK_ERROR) {
protocol_stats_update(STATS_RPL_ROUTELOOP, 1);
tr_info("Forwarding inconsistency R");
rpl_instance_inconsistency(instance);
*result = -1;
return buf;
} else {
opt[2] |= RPL_OPT_RANK_ERROR;
}
}
}
if (buf->rpl_flag_error & RPL_OPT_FWD_ERROR) {
opt[2] |= RPL_OPT_FWD_ERROR;
} else if (rpl_data_is_rpl_downward_route(route_info->source)) {
opt[2] |= RPL_OPT_DOWN;
} else {
opt[2] &= ~RPL_OPT_DOWN;
}
/* Set the D flag for local instances */
if (rpl_instance_id_is_local(instance->id)) {
if (addr_ipv6_equal(dodag->id, buf->dst_sa.address)) {
opt[3] |= RPL_INSTANCE_DEST;
} else if (addr_ipv6_equal(dodag->id, buf->src_sa.address)) {
opt[3] &=~ RPL_INSTANCE_DEST;
} else {
tr_error("Local instance invalid %s[%d]: %s -> %s", trace_ipv6(dodag->id), instance->id, trace_ipv6(buf->src_sa.address), trace_ipv6(buf->dst_sa.address));
*result = -1;
return buf;
}
}
/* RPL 11.2.2.2. says we set SenderRank to infinite when forwarding
* across a version discontinuity. (Must be up - we don't know versions
* of downward routes).
*/
if ((buf->rpl_flag_error & RPL_OPT_FWD_ERROR) || rpl_data_is_rpl_downward_route(route_info->source) || !neighbour || neighbour->dodag_version == instance->current_dodag_version) {
sender_rank = nrpl_dag_rank(dodag, instance->current_rank);
} else {
sender_rank = RPL_RANK_INFINITE;
}
common_write_16_bit(sender_rank, opt + 4);
*result = 0;
return buf;
}
default:
return buffer_free(buf);
}
}
