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MeshCore/src/Mesh.cpp

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#include "Mesh.h"
//#include <Arduino.h>
namespace mesh {
void Mesh::begin() {
Dispatcher::begin();
}
void Mesh::loop() {
Dispatcher::loop();
}
bool Mesh::allowPacketForward(mesh::Packet* packet) {
return false; // by default, Transport NOT enabled
}
int Mesh::searchPeersByHash(const uint8_t* hash) {
return 0; // not found
}
int Mesh::searchChannelsByHash(const uint8_t* hash, GroupChannel channels[], int max_matches) {
return 0; // not found
}
DispatcherAction Mesh::onRecvPacket(Packet* pkt) {
if (pkt->getPayloadVer() > PAYLOAD_VER_1) { // not supported in this firmware version
MESH_DEBUG_PRINTLN("Mesh::onRecvPacket(): unsupported packet version");
return ACTION_RELEASE;
}
if (pkt->isRouteDirect() && pkt->path_len >= PATH_HASH_SIZE) {
if (self_id.isHashMatch(pkt->path) && allowPacketForward(pkt)) {
// remove our hash from 'path', then re-broadcast
pkt->path_len -= PATH_HASH_SIZE;
memcpy(pkt->path, &pkt->path[PATH_HASH_SIZE], pkt->path_len);
return ACTION_RETRANSMIT(0); // Routed traffic is HIGHEST priority
}
return ACTION_RELEASE; // this node is NOT the next hop (OR this packet has already been forwarded), so discard.
}
DispatcherAction action = ACTION_RELEASE;
switch (pkt->getPayloadType()) {
case PAYLOAD_TYPE_ACK: {
int i = 0;
uint32_t ack_crc;
memcpy(&ack_crc, &pkt->payload[i], 4); i += 4;
if (i > pkt->payload_len) {
MESH_DEBUG_PRINTLN("Mesh::onRecvPacket(): incomplete ACK packet");
} else {
onAckRecv(pkt, ack_crc);
action = routeRecvPacket(pkt);
}
break;
}
case PAYLOAD_TYPE_PATH:
case PAYLOAD_TYPE_REQ:
case PAYLOAD_TYPE_RESPONSE:
case PAYLOAD_TYPE_TXT_MSG: {
int i = 0;
uint8_t dest_hash = pkt->payload[i++];
uint8_t src_hash = pkt->payload[i++];
uint8_t* macAndData = &pkt->payload[i]; // MAC + encrypted data
if (i + 2 >= pkt->payload_len) {
MESH_DEBUG_PRINTLN("Mesh::onRecvPacket(): incomplete data packet");
} else {
if (self_id.isHashMatch(&dest_hash)) {
// scan contacts DB, for all matching hashes of 'src_hash' (max 4 matches supported ATM)
int num = searchPeersByHash(&src_hash);
// for each matching contact, try to decrypt data
for (int j = 0; j < num; j++) {
uint8_t secret[PUB_KEY_SIZE];
getPeerSharedSecret(secret, j);
// decrypt, checking MAC is valid
uint8_t data[MAX_PACKET_PAYLOAD];
int len = Utils::MACThenDecrypt(secret, data, macAndData, pkt->payload_len - i);
if (len > 0) { // success!
if (pkt->getPayloadType() == PAYLOAD_TYPE_PATH) {
int k = 0;
uint8_t path_len = data[k++];
uint8_t* path = &data[k]; k += path_len;
uint8_t extra_type = data[k++];
uint8_t* extra = &data[k];
uint8_t extra_len = len - k; // remainder of packet (may be padded with zeroes!)
onPeerPathRecv(pkt, j, path, path_len, extra_type, extra, extra_len);
} else {
onPeerDataRecv(pkt, pkt->getPayloadType(), j, data, len);
}
break;
}
}
}
action = routeRecvPacket(pkt);
}
break;
}
case PAYLOAD_TYPE_ANON_REQ: {
int i = 0;
uint8_t dest_hash = pkt->payload[i++];
uint8_t* sender_pub_key = &pkt->payload[i]; i += PUB_KEY_SIZE;
uint8_t* macAndData = &pkt->payload[i]; // MAC + encrypted data
if (i + 2 >= pkt->payload_len) {
MESH_DEBUG_PRINTLN("Mesh::onRecvPacket(): incomplete data packet");
} else {
if (self_id.isHashMatch(&dest_hash)) {
Identity sender(sender_pub_key);
uint8_t secret[PUB_KEY_SIZE];
self_id.calcSharedSecret(secret, sender);
// decrypt, checking MAC is valid
uint8_t data[MAX_PACKET_PAYLOAD];
int len = Utils::MACThenDecrypt(secret, data, macAndData, pkt->payload_len - i);
if (len > 0) { // success!
onAnonDataRecv(pkt, pkt->getPayloadType(), sender, data, len);
}
}
action = routeRecvPacket(pkt);
}
break;
}
case PAYLOAD_TYPE_GRP_DATA:
case PAYLOAD_TYPE_GRP_TXT: {
int i = 0;
uint8_t channel_hash = pkt->payload[i++];
uint8_t* macAndData = &pkt->payload[i]; // MAC + encrypted data
if (i + 2 >= pkt->payload_len) {
MESH_DEBUG_PRINTLN("Mesh::onRecvPacket(): incomplete data packet");
} else {
// scan channels DB, for all matching hashes of 'channel_hash' (max 2 matches supported ATM)
GroupChannel channels[2];
int num = searchChannelsByHash(&channel_hash, channels, 2);
// for each matching channel, try to decrypt data
for (int j = 0; j < num; j++) {
// decrypt, checking MAC is valid
uint8_t data[MAX_PACKET_PAYLOAD];
int len = Utils::MACThenDecrypt(channels[j].secret, data, macAndData, pkt->payload_len - i);
if (len > 0) { // success!
onGroupDataRecv(pkt, pkt->getPayloadType(), channels[j], data, len);
break;
}
}
action = routeRecvPacket(pkt);
}
break;
}
case PAYLOAD_TYPE_ADVERT: {
int i = 0;
Identity id;
memcpy(id.pub_key, &pkt->payload[i], PUB_KEY_SIZE); i += PUB_KEY_SIZE;
uint32_t timestamp;
memcpy(&timestamp, &pkt->payload[i], 4); i += 4;
uint8_t* signature = &pkt->payload[i]; i += SIGNATURE_SIZE;
if (i > pkt->payload_len) {
MESH_DEBUG_PRINTLN("Mesh::onRecvPacket(): incomplete advertisement packet");
} else {
uint8_t* app_data = &pkt->payload[i];
int app_data_len = pkt->payload_len - i;
if (app_data_len > MAX_ADVERT_DATA_SIZE) { app_data_len = MAX_ADVERT_DATA_SIZE; }
// check that signature is valid
bool is_ok;
{
uint8_t message[PUB_KEY_SIZE + 4 + MAX_ADVERT_DATA_SIZE];
int msg_len = 0;
memcpy(&message[msg_len], id.pub_key, PUB_KEY_SIZE); msg_len += PUB_KEY_SIZE;
memcpy(&message[msg_len], &timestamp, 4); msg_len += 4;
memcpy(&message[msg_len], app_data, app_data_len); msg_len += app_data_len;
is_ok = id.verify(signature, message, msg_len);
}
if (is_ok) {
MESH_DEBUG_PRINTLN("Mesh::onRecvPacket(): valid advertisement received!");
onAdvertRecv(pkt, id, timestamp, app_data, app_data_len);
action = routeRecvPacket(pkt);
} else {
MESH_DEBUG_PRINTLN("Mesh::onRecvPacket(): received advertisement with forged signature!");
}
}
break;
}
default:
MESH_DEBUG_PRINTLN("Mesh::onRecvPacket(): unknown payload type, header: %d", (int) pkt->header);
action = routeRecvPacket(pkt);
break;
}
return action;
}
DispatcherAction Mesh::routeRecvPacket(Packet* packet) {
if (packet->isRouteFlood() && packet->path_len + PATH_HASH_SIZE <= MAX_PATH_SIZE && allowPacketForward(packet)) {
// append this node's hash to 'path'
packet->path_len += self_id.copyHashTo(&packet->path[packet->path_len]);
// as this propagates outwards, give it lower and lower priority
return ACTION_RETRANSMIT(packet->path_len); // give priority to closer sources, than ones further away
}
return ACTION_RELEASE;
}
Packet* Mesh::createAdvert(const LocalIdentity& id, const uint8_t* app_data, size_t app_data_len) {
if (app_data_len > MAX_ADVERT_DATA_SIZE) return NULL;
Packet* packet = obtainNewPacket();
if (packet == NULL) {
MESH_DEBUG_PRINTLN("Mesh::createAdvert(): error, packet pool empty");
return NULL;
}
packet->header = (PAYLOAD_TYPE_ADVERT << PH_TYPE_SHIFT); // ROUTE_TYPE_* is set later
packet->path_len = 0;
int len = 0;
memcpy(&packet->payload[len], id.pub_key, PUB_KEY_SIZE); len += PUB_KEY_SIZE;
uint32_t emitted_timestamp = _rtc->getCurrentTime();
memcpy(&packet->payload[len], &emitted_timestamp, 4); len += 4;
uint8_t* signature = &packet->payload[len]; len += SIGNATURE_SIZE; // will fill this in later
memcpy(&packet->payload[len], app_data, app_data_len); len += app_data_len;
packet->payload_len = len;
{
uint8_t message[PUB_KEY_SIZE + 4 + MAX_ADVERT_DATA_SIZE];
int msg_len = 0;
memcpy(&message[msg_len], id.pub_key, PUB_KEY_SIZE); msg_len += PUB_KEY_SIZE;
memcpy(&message[msg_len], &emitted_timestamp, 4); msg_len += 4;
memcpy(&message[msg_len], app_data, app_data_len); msg_len += app_data_len;
id.sign(signature, message, msg_len);
}
return packet;
}
#define MAX_COMBINED_PATH (MAX_PACKET_PAYLOAD - 2 - CIPHER_BLOCK_SIZE)
Packet* Mesh::createPathReturn(const Identity& dest, const uint8_t* secret, const uint8_t* path, uint8_t path_len, uint8_t extra_type, const uint8_t*extra, size_t extra_len) {
if (path_len + extra_len + 5 > MAX_COMBINED_PATH) return NULL; // too long!!
Packet* packet = obtainNewPacket();
if (packet == NULL) {
MESH_DEBUG_PRINTLN("Mesh::createPathReturn(): error, packet pool empty");
return NULL;
}
packet->header = (PAYLOAD_TYPE_PATH << PH_TYPE_SHIFT); // ROUTE_TYPE_* set later
packet->path_len = 0;
int len = 0;
len += dest.copyHashTo(&packet->payload[len]); // dest hash
len += self_id.copyHashTo(&packet->payload[len]); // src hash
{
int data_len = 0;
uint8_t data[MAX_PACKET_PAYLOAD];
data[data_len++] = path_len;
memcpy(&data[data_len], path, path_len); data_len += path_len;
if (extra_len > 0) {
data[data_len++] = extra_type;
memcpy(&data[data_len], extra, extra_len); data_len += extra_len;
} else {
// append a timestamp, or random blob (to make packet_hash unique)
data[data_len++] = 0xFF; // dummy payload type
getRNG()->random(&data[data_len], 4); data_len += 4;
}
len += Utils::encryptThenMAC(secret, &packet->payload[len], data, data_len);
}
packet->payload_len = len;
return packet;
}
Packet* Mesh::createDatagram(uint8_t type, const Identity& dest, const uint8_t* secret, const uint8_t* data, size_t data_len) {
if (type == PAYLOAD_TYPE_TXT_MSG || type == PAYLOAD_TYPE_REQ || type == PAYLOAD_TYPE_RESPONSE) {
if (data_len + 2 + CIPHER_BLOCK_SIZE-1 > MAX_PACKET_PAYLOAD) return NULL;
} else {
return NULL; // invalid type
}
Packet* packet = obtainNewPacket();
if (packet == NULL) {
MESH_DEBUG_PRINTLN("Mesh::createDatagram(): error, packet pool empty");
return NULL;
}
packet->header = (type << PH_TYPE_SHIFT); // ROUTE_TYPE_* set later
packet->path_len = 0;
int len = 0;
len += dest.copyHashTo(&packet->payload[len]); // dest hash
len += self_id.copyHashTo(&packet->payload[len]); // src hash
len += Utils::encryptThenMAC(secret, &packet->payload[len], data, data_len);
packet->payload_len = len;
return packet;
}
Packet* Mesh::createAnonDatagram(uint8_t type, const LocalIdentity& sender, const Identity& dest, const uint8_t* secret, const uint8_t* data, size_t data_len) {
if (type == PAYLOAD_TYPE_ANON_REQ) {
if (data_len + 1 + PUB_KEY_SIZE + CIPHER_BLOCK_SIZE-1 > MAX_PACKET_PAYLOAD) return NULL;
} else {
return NULL; // invalid type
}
Packet* packet = obtainNewPacket();
if (packet == NULL) {
MESH_DEBUG_PRINTLN("Mesh::createAnonDatagram(): error, packet pool empty");
return NULL;
}
packet->header = (type << PH_TYPE_SHIFT); // ROUTE_TYPE_* set later
packet->path_len = 0;
int len = 0;
if (type == PAYLOAD_TYPE_ANON_REQ) {
len += dest.copyHashTo(&packet->payload[len]); // dest hash
memcpy(&packet->payload[len], sender.pub_key, PUB_KEY_SIZE); len += PUB_KEY_SIZE; // sender pub_key
} else {
// FUTURE:
}
len += Utils::encryptThenMAC(secret, &packet->payload[len], data, data_len);
packet->payload_len = len;
return packet;
}
Packet* Mesh::createGroupDatagram(uint8_t type, const GroupChannel& channel, const uint8_t* data, size_t data_len) {
if (!(type == PAYLOAD_TYPE_GRP_TXT || type == PAYLOAD_TYPE_GRP_DATA)) return NULL; // invalid type
if (data_len + 1 + CIPHER_BLOCK_SIZE-1 > MAX_PACKET_PAYLOAD) return NULL; // too long
Packet* packet = obtainNewPacket();
if (packet == NULL) {
MESH_DEBUG_PRINTLN("Mesh::createGroupDatagram(): error, packet pool empty");
return NULL;
}
packet->header = (type << PH_TYPE_SHIFT); // ROUTE_TYPE_* set later
packet->path_len = 0;
int len = 0;
memcpy(&packet->payload[len], channel.hash, PATH_HASH_SIZE); len += PATH_HASH_SIZE;
len += Utils::encryptThenMAC(channel.secret, &packet->payload[len], data, data_len);
packet->payload_len = len;
return packet;
}
Packet* Mesh::createAck(uint32_t ack_crc) {
Packet* packet = obtainNewPacket();
if (packet == NULL) {
MESH_DEBUG_PRINTLN("Mesh::createAck(): error, packet pool empty");
return NULL;
}
packet->header = (PAYLOAD_TYPE_ACK << PH_TYPE_SHIFT); // ROUTE_TYPE_* set later
packet->path_len = 0;
memcpy(packet->payload, &ack_crc, 4);
packet->payload_len = 4;
return packet;
}
void Mesh::sendFlood(Packet* packet, uint32_t delay_millis) {
packet->header &= ~PH_ROUTE_MASK;
packet->header |= ROUTE_TYPE_FLOOD;
allowPacketForward(packet); // mark this packet as already sent in case it is rebroadcast back to us
uint8_t pri;
if (packet->getPayloadType() == PAYLOAD_TYPE_PATH) {
pri = 2;
} else if (packet->getPayloadType() == PAYLOAD_TYPE_ADVERT) {
pri = 3; // de-prioritie these
} else {
pri = 1;
}
sendPacket(packet, pri, delay_millis);
}
void Mesh::sendDirect(Packet* packet, const uint8_t* path, uint8_t path_len, uint32_t delay_millis) {
packet->header &= ~PH_ROUTE_MASK;
packet->header |= ROUTE_TYPE_DIRECT;
memcpy(packet->path, path, packet->path_len = path_len);
allowPacketForward(packet); // mark this packet as already sent in case it is rebroadcast back to us
sendPacket(packet, 0, delay_millis);
}
void Mesh::sendZeroHop(Packet* packet, uint32_t delay_millis) {
packet->header &= ~PH_ROUTE_MASK;
packet->header |= ROUTE_TYPE_DIRECT;
packet->path_len = 0; // path_len of zero means Zero Hop
allowPacketForward(packet); // mark this packet as already sent in case it is rebroadcast back to us
sendPacket(packet, 0, delay_millis);
}
}
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