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mbed-os/features/nanostack/sal-stack-nanostack/source/RPL/rpl_data.c

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/*
* Copyright (c) 2015-2018, Arm Limited and affiliates.
* SPDX-License-Identifier: Apache-2.0
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/* rpl_data.c deals with handling of the packet data (hop-by-hop header)
* and Source Routing headers in RPL-routed packets.
*
* rpl_domain_t is accessible, but not normally manipulated - all routines in
* this file works on a specific instance.
*
* rpl_instance_t, rpl_dodag_t, rpl_dodag_version_t, rpl_neighbour_t are all accessible.
*/
#include "nsconfig.h"
#ifdef HAVE_RPL
#include "common_functions.h"
#include "nsdynmemLIB.h"
#include "ns_trace.h"
#include <string.h>
#include "Core/include/ns_buffer.h"
#include "NWK_INTERFACE/Include/protocol.h"
#include "NWK_INTERFACE/Include/protocol_stats.h"
#include "Common_Protocols/ipv6.h"
#include "Common_Protocols/ipv6_resolution.h"
#include "Common_Protocols/icmpv6.h"
#include "RPL/rpl_protocol.h"
#include "RPL/rpl_upward.h"
#include "RPL/rpl_downward.h"
#include "RPL/rpl_structures.h"
#include "RPL/rpl_policy.h"
#include "RPL/rpl_data.h"
#include "6LoWPAN/ws/ws_common.h"
#define TRACE_GROUP "RPLa"
#define RPL_DATA_SR_INIT_SIZE (16*4)
#ifdef HAVE_RPL_ROOT
typedef struct rpl_data_sr {
rpl_dao_target_t *target; /* Target - note may be a prefix */
uint16_t iaddr_size;
uint8_t ihops; /* Number of intermediate hops (= addresses in SRH) */
uint8_t final_dest[16]; /* Final destination (used only temporarily during header construction) */
uint8_t iaddr[]; /* Intermediate address list is built backwards, contiguous with final_dest */
} rpl_data_sr_t;
static rpl_data_sr_t *rpl_data_sr;
#endif
static const uint8_t *rpl_data_get_dodagid(const buffer_t *buf);
bool rpl_data_is_rpl_route(ipv6_route_src_t source)
{
switch (source) {
case ROUTE_RPL_DAO:
case ROUTE_RPL_DAO_SR:
case ROUTE_RPL_SRH:
case ROUTE_RPL_DIO:
case ROUTE_RPL_INSTANCE:
case ROUTE_RPL_ROOT:
case ROUTE_RPL_FWD_ERROR:
return true;
default:
return false;
}
}
bool rpl_data_is_rpl_parent_route(ipv6_route_src_t source)
{
switch (source) {
case ROUTE_RPL_DIO:
case ROUTE_RPL_INSTANCE:
case ROUTE_RPL_ROOT:
return true;
default:
return false;
}
}
static bool rpl_data_is_rpl_downward_route(ipv6_route_src_t source)
{
switch (source) {
case ROUTE_RPL_DAO:
case ROUTE_RPL_DAO_SR:
case ROUTE_RPL_SRH:
return true;
default:
return false;
}
}
static bool rpl_data_handle_fwd_error(buffer_t *buf, protocol_interface_info_entry_t *cur, uint8_t *opt, const sockaddr_t *ll_src)
{
if (!ll_src) {
tr_warn("Forwarding-Error - dst=%s, neighbour unknown", trace_ipv6(buf->dst_sa.address));
return false;
} else {
tr_warn("Forwarding-Error - dst=%s, neighbour=%s", trace_ipv6(buf->dst_sa.address), trace_sockaddr(ll_src, true));
}
rpl_instance_t *instance = rpl_lookup_instance(cur->rpl_domain, opt[1], rpl_data_get_dodagid(buf));
if (!instance) {
return false;
}
#if 1
return false;
#else
/* Work needed */
if (rpl_instance_am_root(instance)) {
/* We are looking for a target that has us as its transit */
}
bool deleted = ipv6_route_delete_by_info_and_ll(buf->dst_sa.address, ROUTE_RPL_DAO, ll_src);
deleted |= ipv6_route_delete_by_info_and_ll(buf->dst_sa.address, ROUTE_RPL_DAO_SR, ll_src);
opt[0] &= ~ RPL_OPT_FWD_ERROR;
return true;
#endif
}
bool rpl_data_process_hbh(buffer_t *buf, protocol_interface_info_entry_t *cur, uint8_t *opt, const sockaddr_t *ll_src)
{
buf->rpl_instance = opt[1];
buf->rpl_instance_known = true;
/* Act on the forwarding error */
if (opt[0] & RPL_OPT_FWD_ERROR) {
if (!rpl_data_handle_fwd_error(buf, cur, opt, ll_src)) {
return false;
}
}
/* We don't actually do much now. If the packet is addressed
* to us, we don't need really need much (or any) info.
*
* If we are going to forward forwarding_down will find the option
* manually. If we come to unwrap the tunnel, then we need to take a
* copy before the outer IP header is stripped.
*/
buf->options.ip_extflags |= IPEXT_HBH_RPL;
buf->options.need_predecessor = true;
buf->rpl_flag_error = opt[0];
return true;
}
/* We assume the packet is basically well-formed, as it will have either
* cleared initial input parsing, or we formed it ourselves. hbh and srh
* are set to point to the RPL Hop-by-Hop option and/or RPL Source Routing
* Header, if present.
*/
static void rpl_data_locate_info(buffer_t *buf, uint8_t **hbh, uint8_t **srh)
{
uint8_t *ptr = buffer_data_pointer(buf);
uint16_t len = buffer_data_length(buf);
if (hbh) {
*hbh = NULL;
}
if (srh) {
*srh = NULL;
}
if (len < IPV6_HDRLEN) {
return;
}
uint16_t ip_len = common_read_16_bit(ptr + IPV6_HDROFF_PAYLOAD_LENGTH);
uint8_t nh = ptr[6];
ptr += IPV6_HDRLEN;
len -= IPV6_HDRLEN;
if (ip_len > len) {
return;
}
len = ip_len;
while (len) {
uint16_t hdrlen;
switch (nh) {
case IPV6_NH_HOP_BY_HOP: {
if (len < 8) {
return;
}
nh = ptr[0];
hdrlen = (ptr[1] + 1) * 8;
/* Move on if they're not interested in HbH (looking for SRH) */
if (!hbh) {
break;
}
if (hdrlen > len) {
return;
}
uint8_t *opt_ptr = ptr + 2;
uint8_t *opt_end = ptr + hdrlen;
while (opt_ptr < opt_end) {
switch (opt_ptr[0]) {
case IPV6_OPTION_PAD1:
opt_ptr++;
break;
case IPV6_OPTION_RPL:
*hbh = opt_ptr;
goto found_option;
default:
opt_ptr += 2 + opt_ptr[1];
break;
}
}
found_option:
/* If they're not looking for SRH, finish now */
if (!srh) {
return;
}
break;
}
case IPV6_NH_DEST_OPT:
// Destination option permitted to appear before routing
if (len < 8) {
return;
}
nh = ptr[0];
hdrlen = (ptr[1] + 1) * 8;
/* If they're not looking for SRH, finish now - past HbH */
if (!srh) {
return;
}
break;
case IPV6_NH_ROUTING:
if (!srh) {
return;
}
if (ptr[2] == IPV6_ROUTING_TYPE_RPL) {
*srh = ptr;
}
// No need to examine past routing header
return;
default:
// No other headers can appear before routing - last we care about
return;
}
if (hdrlen > len) {
return;
}
ptr += hdrlen;
len -= hdrlen;
}
return;
}
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;
}
/* Get the DODAG ID if it's a local DODAG packet */
static const uint8_t *rpl_data_get_dodagid(const buffer_t *buf)
{
if (!buf->rpl_instance_known || rpl_instance_id_is_global(buf->rpl_instance)) {
return NULL;
}
/* rpl_data_remember_outer() stores it in the rpl_option metatdata */
if (buf->rpl_option) {
return buf->rpl_option + 1 + buf->rpl_option[1];
} else {
return buf->rpl_instance & RPL_INSTANCE_DEST ? buf->dst_sa.address
: buf->src_sa.address;
}
}
/*
* 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;
// Limit creation of multi-hop RPL packets
// Previous code created multi-hop RPL packets as much as possible,
// sending direct to border router in particular.
// This has caused WiSUN interop problems, so limit this.
// a) When creating a basic packet, have a policy option that prevents
// direct RPL header insertion, forcing tunnelling. This means
// we never put a RPL header on the innermost packet. Option is
// off by default, except for WiSUN, as it increases packet size
// when talking to the border router (eg DAOs).
// b) When putting a packet into a tunnel, set the tunnel exit to the
// next hop always, rather than having a special case for exiting
// at the border router. This is probably a net benefit to packet
// size because of the LL addresses used on the outer header, so
// this is an unconditional change. Exception remains for local
// DODAGs, where the destination address must be the DODAGID.
if (addr_ipv6_equal(route_info->next_hop_addr, buf->dst_sa.address) || (!rpl_policy_force_tunnel() &&
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 */
buf->options.ipv6_use_min_mtu = 1;
*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 always, even if we could tunnel all
// the way to DODAG root (this may be better for
// packet compression, and it was found to be necessary for
// Wi-SUN interoperability). Except for local DODAGs the
// destination must be the DODAGID, so retain that in dst_sa.
if (!rpl_instance_id_is_local(instance->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);
if (sender_rank != 0) {
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);
}
}
static buffer_t *rpl_data_exthdr_provider_hbh(buffer_t *buf, ipv6_exthdr_stage_t stage, int16_t *result)
{
ipv6_route_info_t *route_info = &buf->route->route_info;
rpl_neighbour_t *neighbour = route_info->info;
rpl_instance_t *instance = rpl_neighbour_instance(neighbour);
if (!instance) {
*result = -1;
return buf;
}
return rpl_data_exthdr_provider_hbh_2(buf, instance, neighbour, stage, result);
}
static buffer_t *rpl_data_exthdr_provider_fwd_error_hbh(buffer_t *buf, ipv6_exthdr_stage_t stage, int16_t *result)
{
ipv6_route_info_t *route_info = &buf->route->route_info;
rpl_instance_t *instance = route_info->info;
return rpl_data_exthdr_provider_hbh_2(buf, instance, NULL, stage, result);
}
/* This could live in address.c or ipv6.c */
/* Can get false negatives if we don't already have a neighbour cache entry, but in practice
* will be solid as we are basically matching link-local 6LoWPAN addresses, which can be mapped
* to link-layer without an existing entry. Could conceivably get a false positive if we have
* a stale entry and MAC addresses have been reassigned, but very unlikely.
*/
static bool rpl_downward_ip_addr_matches_ll_addr(protocol_interface_info_entry_t *cur, const uint8_t ip_addr_a[static 16], const sockaddr_t *ll_addr_b)
{
if (!ll_addr_b) {
return false;
}
addrtype_t ll_type_a;
const uint8_t *ll_addr_a;
if (!ipv6_map_ip_to_ll(cur, NULL, ip_addr_a, &ll_type_a, &ll_addr_a)) {
return false;
}
return ll_type_a == ll_addr_b->addr_type &&
memcmp(ll_addr_a, ll_addr_b->address, addr_len_from_type(ll_type_a)) == 0;
}
/* ROUTE_RPL_INSTANCE routes are the default for the instance - not valid, unless
* instance is already known.
*/
static bool rpl_data_route_predicate_instance_default(const ipv6_route_info_t *route, bool valid)
{
(void)route;
(void)valid;
return false;
}
static rpl_instance_t *predicate_instance;
static bool predicate_down;
static const sockaddr_t *predicate_predecessor;
/* Override predicate for choosing routes given a specific instance (ie when
* forwarding a packet that had a specified instance ID). That instance is
* loaded into the static predicate_instance above.
*/
static bool rpl_data_route_predicate_specific_instance(const ipv6_route_info_t *route, bool valid)
{
/* We will permit forwarding out of RPL into a non-RPL interface (eg border routers) */
/* XXX - what if we're the boundary between two RPL domains? */
protocol_interface_info_entry_t *cur = protocol_stack_interface_info_get_by_id(route->interface_id);
if (!cur || !cur->rpl_domain) {
return valid;
}
/* If forwarding onto the same interface, think more */
switch (route->source) {
/* These are the type of routes we will forward onto out of RPL - they
* must include all types of non-owned routes that could be advertised
* through a DAO.
*/
case ROUTE_ARO:
return valid;
/* Upward routes */
case ROUTE_RPL_DIO:
case ROUTE_RPL_INSTANCE:
case ROUTE_RPL_ROOT: {
/* Packets going down can't go back up */
if (predicate_down) {
return false;
}
/* Never route to predecessor */
if (rpl_downward_ip_addr_matches_ll_addr(cur, route->next_hop_addr, predicate_predecessor)) {
return false;
}
/* Info for these upward routes is a back pointer to the neighbour */
rpl_neighbour_t *neighbour = route->info;
/* From there, we can get the instance info */
rpl_instance_t *instance = rpl_neighbour_instance(neighbour);
/* Note that this overrides the default "false" for INSTANCE routes */
return instance == predicate_instance;
}
/* Downward routes */
case ROUTE_RPL_DAO:
case ROUTE_RPL_DAO_SR: {
/* Info for these downward routes is a back pointer to the target */
rpl_dao_target_t *target = route->info;
/* Going to predecessor is fine if it was going up - we are reversing to down. Otherwise block */
if (predicate_down) {
if (rpl_downward_ip_addr_matches_ll_addr(cur, route->next_hop_addr, predicate_predecessor)) {
return false;
}
}
return target->instance == predicate_instance;
}
/* Unknown */
default:
return false;
}
}
ipv6_route_predicate_fn_t *rpl_data_get_route_predicate(rpl_domain_t *domain, const buffer_t *buf)
{
const uint8_t *dodagid = rpl_data_get_dodagid(buf);
predicate_instance = rpl_lookup_instance(domain, buf->rpl_instance, dodagid);
predicate_down = buf->rpl_flag_error & RPL_OPT_DOWN;
predicate_predecessor = buf->predecessor;
return rpl_data_route_predicate_specific_instance;
}
/* Returns true if we are going to pass this back with the 'F' bit set */
/* If we return false, a "no route" ICMP error will occur as normal */
/* For the ICMP error case, we may treat as a DIO Trickle inconsistency, as
* suggested by RFC 6550 11.1(8) */
bool rpl_data_forwarding_error(buffer_t *buf)
{
/* This is called when we have no route to send a packet - first check
* if we were forwarding it for RPL - indicated by rpl_instance_known.
*/
if (!buf->rpl_instance_known) {
return false;
}
protocol_interface_info_entry_t *cur = buf->interface;
if (!cur) {
return false;
}
rpl_instance_t *instance = rpl_lookup_instance(cur->rpl_domain, buf->rpl_instance, rpl_data_get_dodagid(buf));
if (!instance) {
tr_err("rpl_data_forwarding_error: unknown instance");
return false;
}
/* To use Forwarding-Error, packet must be Down, and must know predecessor */
if (!((buf->rpl_flag_error & RPL_OPT_DOWN) && buf->predecessor)) {
goto not_forwarding_error;
}
/* Must then be able to map predecessor to IP address */
uint8_t predecessor_ip[16];
if (!ipv6_map_ll_to_ip_link_local(cur, buf->predecessor->addr_type, buf->predecessor->address, predecessor_ip)) {
return false;
}
buf->rpl_flag_error |= RPL_OPT_FWD_ERROR;
buffer_free_route(buf);
if (!ipv6_buffer_route_to(buf, predecessor_ip, buf->interface)) {
return false;
}
buf->route->route_info.info = instance;
buf->route->route_info.source = ROUTE_RPL_FWD_ERROR;
return true;
not_forwarding_error:
/* If we're not signalling a Forwarding-Error, we will be sending
* an ICMP Destination Unreachable to the source as normal. But we
* may still want to attempt some sort of RPL repair. If it was coming
* upwards, and we're _not_ the root of the instance, a failure to
* pass it on can only mean some sort of RPL routing problem (eg refusing
* to pass to the predecessor), as we should normally be able to send
* towards the DODAG root. We attempt to aid repair by triggering
* a DIO inconsistency.
*
* If we are the root, then it will just be a perfectly normal
* "destination unreachable" - it doesn't suggest a RPL repair is needed.
*/
if (!(buf->rpl_flag_error & RPL_OPT_DOWN) && !rpl_instance_am_root(instance)) {
protocol_stats_update(STATS_RPL_ROUTELOOP, 1);
tr_info("Forwarding inconsistency 2");
rpl_instance_inconsistency(instance);
}
return false;
}
#ifdef HAVE_RPL_ROOT
/* TODO - every target involved here should be non-External. Add checks */
static bool rpl_data_compute_source_route(const uint8_t *final_dest, rpl_dao_target_t *const target)
{
if (!rpl_data_sr) {
rpl_data_sr = rpl_alloc(sizeof(rpl_data_sr_t) + RPL_DATA_SR_INIT_SIZE);
if (!rpl_data_sr) {
return false;
}
rpl_data_sr->iaddr_size = RPL_DATA_SR_INIT_SIZE;
rpl_data_sr->target = NULL;
} else if (rpl_data_sr->target == target && addr_ipv6_equal(rpl_data_sr->final_dest, final_dest)) {
return true;
}
/* This does all the heavy lifting - after running, the optimum path from
* every target node is at the front of the transit list, and the connected
* flag is set if we've any prospect.
*/
rpl_downward_compute_paths(target->instance);
if (!target->connected) {
return false;
}
/* Wipe the "data valid" marker */
rpl_data_sr->target = NULL;
rpl_data_sr->ihops = 0;
/* Final destination written explicitly (last target could be a prefix) */
memcpy(rpl_data_sr->final_dest, final_dest, 16);
/* We just work backwards from the target, following the first transit
* each time, which is the shortest path after the compute_paths call.
*/
rpl_dao_target_t *t = target;
for (;;) {
/* First transit is best path, thanks to root computation above */
rpl_dao_root_transit_t *transit = ns_list_get_first(&t->info.root.transits);
rpl_dao_target_t *parent = transit->parent;
/* Finished if we hit NULL - ourselves */
if (parent == NULL) {
/* Mark "valid" */
rpl_data_sr->target = target;
return true;
}
if (!parent->connected) {
tr_err("Parent %s disconnected", trace_ipv6_prefix(parent->prefix, parent->prefix_len));
return false;
}
/* Check transit address isn't already in table. Should not be possible */
for (int i = 16 * rpl_data_sr->ihops; i >= 0; i -= 16) {
if (addr_ipv6_equal(rpl_data_sr->final_dest + i, transit->transit)) {
protocol_stats_update(STATS_RPL_ROUTELOOP, 1);
tr_err("SR loop %s->%s", trace_ipv6_prefix(t->prefix, t->prefix_len), trace_ipv6(transit->transit));
return false;
}
}
/* Increase size of table if necessary */
if (16 * (rpl_data_sr->ihops + 1) > rpl_data_sr->iaddr_size) {
rpl_data_sr = rpl_realloc(rpl_data_sr, sizeof(rpl_data_sr_t) + rpl_data_sr->iaddr_size, sizeof(rpl_data_sr_t) + 2 * rpl_data_sr->iaddr_size);
if (!rpl_data_sr) {
return false;
}
rpl_data_sr->iaddr_size *= 2;
}
memcpy(rpl_data_sr->iaddr + 16 * rpl_data_sr->ihops, transit->transit, 16);
rpl_data_sr->ihops += 1;
t = parent;
}
}
/* Return the next hop, if there is an intermediate. If it's direct, NULL
* is returned. This call must follow a successful call to
* rpl_data_compute_source_route().
*/
const uint8_t *rpl_data_sr_next_hop(void)
{
if (rpl_data_sr->ihops == 0) {
return NULL;
}
return rpl_data_sr->iaddr + 16 * (rpl_data_sr->ihops - 1);
}
static bool rpl_data_route_next_hop(const uint8_t *dest, ipv6_route_info_t *route)
{
rpl_dao_target_t *target = route->info;
if (!rpl_data_compute_source_route(dest, target)) {
return false;
}
const uint8_t *next_hop = rpl_data_sr_next_hop();
if (next_hop) {
memcpy(route->next_hop_addr, next_hop, 16);
} else {
memcpy(route->next_hop_addr, dest, 16);
}
return true;
}
void rpl_data_sr_invalidate(void)
{
if (rpl_data_sr) {
rpl_data_sr->target = NULL;
rpl_data_sr->ihops = 0;
}
/* We could invalidate the next hops remembered in the system routing table.
* but it's not necessary - recomputation happens every time. Does mean that
* the routing table printout may contain stale info, though.
*/
}
typedef struct rpl_srh_info {
uint8_t hlen;
uint8_t segments;
uint8_t cmprI;
uint8_t cmprE;
uint8_t pad;
} rpl_srh_info_t;
/* Count matching bytes (max 15) for SRH compression */
static uint_fast8_t rpl_data_matching_addr_bytes(const uint8_t *a, const uint8_t *b, uint_fast8_t len)
{
uint_fast8_t m = 0;
while (m < len && a[m] == b[m]) {
m++;
}
return m;
}
static const rpl_srh_info_t *rpl_data_sr_compute_header_size(const uint8_t final_dest[16], uint8_t hop_limit)
{
static rpl_srh_info_t info;
uint8_t hops = 1 + rpl_data_sr->ihops;
if (hops > hop_limit) {
hops = hop_limit;
}
if (hops <= 1) {
return NULL;
}
memcpy(rpl_data_sr->final_dest, final_dest, 16);
/* first_hop is the address that will go into the IP destination */
const uint8_t *first_hop = rpl_data_sr->iaddr + 16 * (rpl_data_sr->ihops - 1);
/* addr is the first address for the SRH */
const uint8_t *addr = first_hop - 16;
/* Must be at least 2 hops, so at least 1 segment in the SRH */
info.segments = hops - 1;
/* First, scan for compression of all except last against initial destination */
/* (CmprI bytes will remain unchanged at each hop, rest can change) */
info.cmprI = 15;
for (uint8_t seg = 0; seg < info.segments - 1; seg++) {
info.cmprI = rpl_data_matching_addr_bytes(addr, first_hop, info.cmprI);
hops--;
addr -= 16;
}
/* Compress last hop against previous destination */
/* Debatable whether we should let cmprE be > cmprI - it means the final
* address won't be IP_dest[0:cmprI)+Address_n[cmprI:64) until the final
* hop (segments left = 1):
*
* CmprI = 14, CmprE = 15
* IP dest Segs Left Addresses
* x:1234 3 2345, 3456, 22 <- meaning "3422", not "1222"
* x:2345 2 1234, 3456, 22
* x:3456 1 1234, 2345, 22
* x:3422 0 1234, 2345, 56
*
* But then similar issues arise if cmprE < cmprI:
*
* CmprI = 15, CmprE = 14
* IP dest Segs Left Addresses
* x:1234 3 45, 56, ABCD
* x:1245 2 34, 56, ABCD
* x:1256 1 34, 45, ABCD
* x:ABCD 0 34, 45, 1256 <- "45" means "1245", not "AB45"
*
* Basically, there's no loss of information, but it's not as straightforward
* as RFC 6554 says. If cmprI != cmprE, not all Address entries represent
* addresses with the same prefix as the IP destination at any given
* instant. (But the next address to process does line up with the current
* IP destination).
*
*/
info.cmprE = rpl_data_matching_addr_bytes(addr, addr + 16, 15 /* info.cmprI */);
uint16_t total_size;
total_size = (16 - info.cmprE) + (16 - info.cmprI) * (info.segments - 1);
if (total_size & 7) {
info.pad = 8 - (total_size & 7);
total_size += info.pad;
} else {
info.pad = 0;
}
info.hlen = total_size >> 3;
return &info;
}
/*
* 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
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | Next Header | Hdr Ext Len | Routing Type | Segments Left |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | CmprI | CmprE | Pad | Reserved |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | |
* . .
* . Addresses[1..n] .
* . .
* | |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*/
static uint8_t *rpl_data_sr_write_header(const rpl_srh_info_t *info, uint8_t *ptr, uint8_t nh)
{
ptr[0] = nh;
ptr[1] = info->hlen;
ptr[2] = IPV6_ROUTING_TYPE_RPL;
ptr[3] = info->segments;
ptr[4] = (info->cmprI << 4) | info->cmprE;
ptr[5] = (info->pad << 4);
common_write_16_bit(0, ptr + 6);
ptr += 8;
const uint8_t *addr = rpl_data_sr->iaddr + 16 * (rpl_data_sr->ihops - 2);
for (int n = 0; n < info->segments - 1; n++) {
memcpy(ptr, addr + info->cmprI, 16 - info->cmprI);
ptr += 16 - info->cmprI;
addr -= 16;
}
memcpy(ptr, addr + info->cmprE, 16 - info->cmprE);
ptr += 16 - info->cmprE;
if (info->pad) {
memset(ptr, 0, info->pad);
ptr += info->pad;
}
return ptr;
}
static buffer_t *rpl_data_exthdr_provider_srh(buffer_t *buf, ipv6_exthdr_stage_t stage, int16_t *result)
{
ipv6_route_info_t *route_info = &buf->route->route_info;
rpl_dao_target_t *target = route_info->info;
rpl_instance_t *instance = target->instance;
if (!instance) {
*result = -1;
return buf;
}
uint16_t ext_size = 0;
const rpl_srh_info_t *srh_info = NULL;
const uint8_t *final_rpl_dest = buf->dst_sa.address;
if (target->external) {
/* If we haven't yet tunnelled, then there's no insertion */
if (!buf->options.tunnelled) {
if (stage == IPV6_EXTHDR_SIZE || stage == IPV6_EXTHDR_INSERT) {
*result = 0;
buf->options.ipv6_use_min_mtu = 1;
return buf;
}
}
/* If it's an external target, we need to only go as far as its transit */
/* Modify target to point to that instead */
rpl_dao_root_transit_t *transit = ns_list_get_first(&target->info.root.transits);
if (!transit) {
*result = -1;
return buf;
}
final_rpl_dest = transit->transit;
target = rpl_instance_match_dao_target(instance, final_rpl_dest, 128);
if (!target) {
*result = -1;
return buf;
}
}
if (!rpl_data_compute_source_route(final_rpl_dest, target)) {
*result = -1;
return buf;
}
/* When tunnelling (only), we truncate the route in the outer packet,
* according to the hop limit, so it exits the tunnel at the hop limit -
* that router will then generate "time exceeded" on the inner packet.
* (RFC 6554 4.1). When not tunnelling, we include all hops regardless,
* which means the final destination is there as needed.
*/
srh_info = rpl_data_sr_compute_header_size(final_rpl_dest, buf->options.tunnelled && buf->options.type == IPV6_NH_IPV6 ? buf->options.hop_limit : 0xFF);
if (!srh_info) {
/* No source routing header required - this must be because it's one hop. */
/* In this case, we do need to add a HbH option header */
return rpl_data_exthdr_provider_hbh_2(buf, instance, NULL, stage, result);
}
ext_size = 8 * (srh_info->hlen + 1);
switch (stage) {
case IPV6_EXTHDR_SIZE:
*result = ext_size;
return buf;
case IPV6_EXTHDR_INSERT: {
buf = buffer_headroom(buf, ext_size);
if (!buf) {
return NULL;
}
uint8_t *ext = buffer_data_reserve_header(buf, ext_size);
rpl_data_sr_write_header(srh_info, ext, buf->options.type);
buf->route->ip_dest = rpl_data_sr_next_hop();
buf->options.type = IPV6_NH_ROUTING;
// don't forget to set the "RPL option present" marker
buf->options.ip_extflags |= IPEXT_SRH_RPL;
*result = 0;
return buf;
}
case IPV6_EXTHDR_MODIFY:
if (buf->options.ip_extflags & IPEXT_SRH_RPL) {
*result = 0;
return buf;
}
if (final_rpl_dest != buf->dst_sa.address) {
memcpy(buf->dst_sa.address, final_rpl_dest, 16);
}
*result = IPV6_EXTHDR_MODIFY_TUNNEL;
buf->src_sa.addr_type = ADDR_NONE; // force auto-selection
return buf;
default:
return buffer_free(buf);
}
}
#endif // HAVE_RPL_ROOT
buffer_t *rpl_data_process_routing_header(buffer_t *buf, protocol_interface_info_entry_t *cur, uint8_t *ptr, uint16_t *hdrlen_out, bool *forward_out)
{
/* Handling procedures based on RFC 6554 4.2 */
/* Do not process RPL source routing headers unless they arrive on a RPL interface */
if (!cur->rpl_domain) {
tr_warn("SRH RX non-RPL if");
drop:
protocol_stats_update(STATS_IP_RX_DROP, 1);
return buffer_free(buf);
}
buf->options.ip_extflags |= IPEXT_SRH_RPL;
if (ws_info(cur)) {
//Call SRC route header handler hook to Wi-SUN refresh border router alive
ws_common_border_router_alive_update(cur);
}
uint16_t hlen = (ptr[1] + 1) * 8;
uint8_t segs_left = ptr[3];
if (segs_left == 0) {
*hdrlen_out = hlen;
return buf;
}
uint8_t cmprI = ptr[4] >> 4;
uint8_t cmprE = ptr[4] & 0xF;
uint8_t pad = ptr[5] >> 4;
/* Should really be more rigorous here */
uint_fast16_t n_addrs = ((hlen - 8 - pad - (16 - cmprE)) / (16 - cmprI)) + 1;
if (segs_left > n_addrs) {
return icmpv6_error(buf, cur, ICMPV6_TYPE_ERROR_PARAMETER_PROBLEM, ICMPV6_CODE_PARAM_PRB_HDR_ERR, (ptr + 3) - buffer_data_pointer(buf));
}
uint8_t *ip_dst = buffer_data_pointer(buf) + 24;
/* Decrement segments left */
segs_left = --ptr[3];
if (addr_is_ipv6_multicast(buf->dst_sa.address)) {
goto drop;
}
/* Next address index (starting at 1, as per RFC 6554) */
uint_fast16_t next_addr_i = n_addrs - segs_left;
/* Locate next address: aptr -> Address[i] */
uint8_t *aptr = ptr + 8 + (next_addr_i - 1) * (16 - cmprI);
uint8_t cmpr = next_addr_i == n_addrs ? cmprE : cmprI;
uint8_t asize = 16 - cmpr;
/* Next address can only be multicast if compression is 0, otherwise
* it inherits an already-checked non-0xFF start byte from IP destination
*/
if (cmpr == 0 && addr_is_ipv6_multicast(aptr)) {
goto drop;
}
/* Look for a loop. Scanning all addresses 1..n would be a pain, given
* the possibility of weird cmprI/E combinations. But there's logically
* no need to look at _previous_ addresses. And we know the packet was
* addressed to us to reach us - Address[i-1] must have been ours. So
* to ensure we do the test in RFC 6554:
*
* if 2 or more entries in Address[1..n] are assigned to
* local interface and are separated by at least one
* address not assigned to local interface
*
* We just check Address[i..n], knowing that i-1 was ours. It's impossible
* for anything older than i-1 to be ours, as we would have failed the
* check previously...
*
* There need to be at least 2 more addresses (i and i+1) for this check
* to be useful.
*/
if (next_addr_i + 1 <= n_addrs) {
uint8_t addr[16];
/* We know Address[i-1] was ours */
bool prev_was_local = true;
/* Initialise pointers to examine Address[i] */
memcpy(addr, ip_dst, 16);
const uint8_t *a = aptr;
/* Then scan remaining */
for (uint_fast16_t i = next_addr_i; i <= n_addrs; i++) {
uint8_t cpr = i == n_addrs ? cmprE : cmprI;
uint8_t asz = 16 - cpr;
memcpy(addr + cpr, a, asz);
a += asz;
bool local_addr = addr_interface_address_compare(cur, addr) == 0;
if (local_addr) {
if (!prev_was_local) {
protocol_stats_update(STATS_RPL_ROUTELOOP, 1);
tr_warn("SRH loop");
return icmpv6_error(buf, cur, ICMPV6_TYPE_ERROR_PARAMETER_PROBLEM, ICMPV6_CODE_PARAM_PRB_HDR_ERR, aptr - buffer_data_pointer(buf));
}
}
prev_was_local = local_addr;
}
}
/* Swap the destination and Address[i] */
memswap(ip_dst + cmpr, aptr, asize);
/* And update the metadata */
memcpy(buf->dst_sa.address, ip_dst, 16);
/* Need to fake up routing here. Basically, for the common (shared-prefix)
* case, we have to assume that the destination is on-link, on an assumed
* interface. We have no direct record of the people trying to use us
* as DAO parents, so we will get totally unknown addresses in SRHs.
* We add routing info to the buffer to say that the IP destination is
* the next hop, and the source being "SRH" is the IP layer's cue to send
* "Error in Source Routing Header" codes instead of "Address Unreachable".
*/
buffer_free_route(buf);
/* THINK: May want to check to see if the address is already known to be on-link on
* an interface. Won't be the usual 6LoWPAN case though.
*/
/* Policy gets to decide whether we will take this - it can do neighbour state checks */
protocol_interface_info_entry_t *next_if =
protocol_stack_interface_info_get_by_id(
rpl_policy_srh_next_hop_interface(cur->rpl_domain, cur->id,
buf->dst_sa.address));
if (!next_if) {
goto error;
}
buffer_routing_info_t *route = ipv6_buffer_route_to(buf, buf->dst_sa.address, next_if);
if (!route) {
/* Shouldn't happen here? Out of memory case? */
goto error;
}
route->route_info.source = ROUTE_RPL_SRH;
*forward_out = true;
return buf;
error:
return icmpv6_error(buf, cur, ICMPV6_TYPE_ERROR_DESTINATION_UNREACH, ICMPV6_CODE_DST_UNREACH_SRC_RTE_HDR_ERR, 0);
}
bool rpl_data_get_srh_last_address(const uint8_t *rh, uint8_t *addr_out)
{
uint_fast8_t len = rh[1];
uint_fast8_t segs_left = rh[3];
uint_fast8_t cmpr_i = rh[4] >> 4;
uint_fast8_t cmpr_e = rh[4] & 0xF;
uint_fast8_t pad = rh[5] >> 4;
const uint8_t *last_addr_ptr = rh + 8 + (len * 8) - pad - (16 - cmpr_e);
if (segs_left == 0) {
return true;
}
if (segs_left > 1) {
/* Get last "I" destination in */
memcpy(addr_out + cmpr_i, last_addr_ptr - (16 - cmpr_i), 16 - cmpr_i);
}
/* Then modify "E" destination */
memcpy(addr_out + cmpr_e, last_addr_ptr, 16 - cmpr_e);
return true;
}
/* Set up handlers for general RPL nodes (hop-by-hop headers, DIO routes) */
void rpl_data_init(void)
{
ipv6_route_table_set_predicate_fn(ROUTE_RPL_INSTANCE, rpl_data_route_predicate_instance_default);
ipv6_set_exthdr_provider(ROUTE_RPL_INSTANCE, rpl_data_exthdr_provider_hbh);
ipv6_set_exthdr_provider(ROUTE_RPL_DIO, rpl_data_exthdr_provider_hbh);
ipv6_set_exthdr_provider(ROUTE_RPL_ROOT, rpl_data_exthdr_provider_hbh);
ipv6_set_exthdr_provider(ROUTE_RPL_FWD_ERROR, rpl_data_exthdr_provider_fwd_error_hbh);
}
#ifdef HAVE_RPL_ROOT
/* Set up handlers for DODAG root (creation of source routing headers) */
void rpl_data_init_root(void)
{
ipv6_set_exthdr_provider(ROUTE_RPL_DAO_SR, rpl_data_exthdr_provider_srh);
ipv6_route_table_set_next_hop_fn(ROUTE_RPL_DAO_SR, rpl_data_route_next_hop);
}
#endif
#endif /* HAVE_RPL */
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