stub encryptor seems nicely backwards compatible with old devices and apps

proto

@@ -1 +1 @@
-Subproject commit 1a5afe8f567866981ac0cd0a75a95503064d33c2
+Subproject commit f775ebe369cd9bd92d954d46f76ea0a4ae62078c

src/mesh/CryptoEngine.cpp

@@ -11,6 +11,12 @@ void CryptoEngine::setKey(size_t numBytes, const uint8_t *bytes)
  *
  * @param bytes is updated in place
  */
-void CryptoEngine::encrypt(uint32_t fromNode, uint64_t packetNum, size_t numBytes, uint8_t *bytes) {}
+void CryptoEngine::encrypt(uint32_t fromNode, uint64_t packetNum, size_t numBytes, uint8_t *bytes)
+{
+    DEBUG_MSG("WARNING: noop encryption!\n");
+}
 
-void CryptoEngine::decrypt(uint32_t fromNode, uint64_t packetNum, size_t numBytes, uint8_t *bytes) {}
+void CryptoEngine::decrypt(uint32_t fromNode, uint64_t packetNum, size_t numBytes, uint8_t *bytes)
+{
+    DEBUG_MSG("WARNING: noop decryption!\n");
+}

src/mesh/MeshService.cpp

@@ -92,9 +92,9 @@ void MeshService::sendOurOwner(NodeNum dest, bool wantReplies)
 {
     MeshPacket *p = allocForSending();
     p->to = dest;
-    p->payload.want_response = wantReplies;
+    p->decoded.want_response = wantReplies;
-    p->payload.has_user = true;
+    p->decoded.has_user = true;
-    User &u = p->payload.user;
+    User &u = p->decoded.user;
     u = owner;
     DEBUG_MSG("sending owner %s/%s/%s\n", u.id, u.long_name, u.short_name);
 
@@ -108,7 +108,7 @@ const MeshPacket *MeshService::handleFromRadioUser(const MeshPacket *mp)
     bool isCollision = mp->from == myNodeInfo.my_node_num;
 
     // we win if we have a lower macaddr
-    bool weWin = memcmp(&owner.macaddr, &mp->payload.user.macaddr, sizeof(owner.macaddr)) < 0;
+    bool weWin = memcmp(&owner.macaddr, &mp->decoded.user.macaddr, sizeof(owner.macaddr)) < 0;
 
     if (isCollision) {
         if (weWin) {
@@ -134,7 +134,7 @@ const MeshPacket *MeshService::handleFromRadioUser(const MeshPacket *mp)
 
         sendOurOwner(mp->from);
 
-        String lcd = String("Joined: ") + mp->payload.user.long_name + "\n";
+        String lcd = String("Joined: ") + mp->decoded.user.long_name + "\n";
         screen.print(lcd.c_str());
     }
 
@@ -143,12 +143,12 @@ const MeshPacket *MeshService::handleFromRadioUser(const MeshPacket *mp)
 
 void MeshService::handleIncomingPosition(const MeshPacket *mp)
 {
-    if (mp->has_payload && mp->payload.has_position) {
+    if (mp->which_payload == MeshPacket_decoded_tag && mp->decoded.has_position) {
-        DEBUG_MSG("handled incoming position time=%u\n", mp->payload.position.time);
+        DEBUG_MSG("handled incoming position time=%u\n", mp->decoded.position.time);
 
-        if (mp->payload.position.time) {
+        if (mp->decoded.position.time) {
             struct timeval tv;
-            uint32_t secs = mp->payload.position.time;
+            uint32_t secs = mp->decoded.position.time;
 
             tv.tv_sec = secs;
             tv.tv_usec = 0;
@@ -171,7 +171,7 @@ int MeshService::handleFromRadio(const MeshPacket *mp)
         DEBUG_MSG("Ignoring incoming time, because we have a GPS\n");
     }
 
-    if (mp->has_payload && mp->payload.has_user) {
+    if (mp->which_payload == MeshPacket_decoded_tag && mp->decoded.has_user) {
         mp = handleFromRadioUser(mp);
     }
 
@@ -192,7 +192,7 @@ int MeshService::handleFromRadio(const MeshPacket *mp)
         MeshPacket *copied = packetPool.allocCopy(*mp);
         assert(toPhoneQueue.enqueue(copied, 0)); // FIXME, instead of failing for full queue, delete the oldest mssages
 
-        if (mp->payload.want_response)
+        if (mp->decoded.want_response)
             sendNetworkPing(mp->from);
     } else {
         DEBUG_MSG("Not delivering vetoed User message\n");
@@ -257,12 +257,12 @@ void MeshService::sendToMesh(MeshPacket *p)
     // Strip out any time information before sending packets to other  nodes - to keep the wire size small (and because other
     // nodes shouldn't trust it anyways) Note: for now, we allow a device with a local GPS to include the time, so that gpsless
     // devices can get time.
-    if (p->has_payload && p->payload.has_position) {
+    if (p->which_payload == MeshPacket_decoded_tag && p->decoded.has_position) {
         if (!gps->isConnected) {
-            DEBUG_MSG("Stripping time %u from position send\n", p->payload.position.time);
+            DEBUG_MSG("Stripping time %u from position send\n", p->decoded.position.time);
-            p->payload.position.time = 0;
+            p->decoded.position.time = 0;
         } else
-            DEBUG_MSG("Providing time to mesh %u\n", p->payload.position.time);
+            DEBUG_MSG("Providing time to mesh %u\n", p->decoded.position.time);
     }
 
     // If the phone sent a packet just to us, don't send it out into the network
@@ -282,7 +282,7 @@ MeshPacket *MeshService::allocForSending()
 {
     MeshPacket *p = packetPool.allocZeroed();
 
-    p->has_payload = true;
+    p->which_payload = MeshPacket_decoded_tag; // Assume payload is decoded at start.
     p->from = nodeDB.getNodeNum();
     p->to = NODENUM_BROADCAST;
     p->id = generatePacketId();
@@ -312,10 +312,10 @@ void MeshService::sendOurPosition(NodeNum dest, bool wantReplies)
     // Update our local node info with our position (even if we don't decide to update anyone else)
     MeshPacket *p = allocForSending();
     p->to = dest;
-    p->payload.has_position = true;
+    p->decoded.has_position = true;
-    p->payload.position = node->position;
+    p->decoded.position = node->position;
-    p->payload.want_response = wantReplies;
+    p->decoded.want_response = wantReplies;
-    p->payload.position.time = getValidTime(); // This nodedb timestamp might be stale, so update it if our clock is valid.
+    p->decoded.position.time = getValidTime(); // This nodedb timestamp might be stale, so update it if our clock is valid.
     sendToMesh(p);
 }
 
@@ -325,9 +325,9 @@ int MeshService::onGPSChanged(void *unused)
 
     // Update our local node info with our position (even if we don't decide to update anyone else)
     MeshPacket *p = allocForSending();
-    p->payload.has_position = true;
+    p->decoded.has_position = true;
 
-    Position &pos = p->payload.position;
+    Position &pos = p->decoded.position;
     // !zero or !zero lat/long means valid
     if (gps->latitude != 0 || gps->longitude != 0) {
         if (gps->altitude != 0)

src/mesh/NodeDB.cpp

@@ -274,8 +274,8 @@ size_t NodeDB::getNumOnlineNodes()
 /// we updateGUI and updateGUIforNode if we think our this change is big enough for a redraw
 void NodeDB::updateFrom(const MeshPacket &mp)
 {
-    if (mp.has_payload) {
+    if (mp.which_payload == MeshPacket_decoded_tag) {
-        const SubPacket &p = mp.payload;
+        const SubPacket &p = mp.decoded;
         DEBUG_MSG("Update DB node 0x%x, rx_time=%u\n", mp.from, mp.rx_time);
 
         int oldNumNodes = *numNodes;

src/mesh/RadioInterface.cpp

@@ -107,7 +107,7 @@ size_t RadioInterface::beginSending(MeshPacket *p)
     assert(!sendingPacket);
 
     // DEBUG_MSG("sending queued packet on mesh (txGood=%d,rxGood=%d,rxBad=%d)\n", rf95.txGood(), rf95.rxGood(), rf95.rxBad());
-    assert(p->has_payload);
+    assert(p->which_payload == MeshPacket_encrypted_tag); // It should have already been encoded by now
 
     lastTxStart = millis();
 
@@ -121,11 +121,8 @@ size_t RadioInterface::beginSending(MeshPacket *p)
     // if the sender nodenum is zero, that means uninitialized
     assert(h->from);
 
-    size_t numbytes = pb_encode_to_bytes(radiobuf + sizeof(PacketHeader), sizeof(radiobuf), SubPacket_fields, &p->payload) +
+    memcpy(radiobuf + sizeof(PacketHeader), p->encrypted.bytes, p->encrypted.size);
-                      sizeof(PacketHeader);
-
-    assert(numbytes <= MAX_RHPACKETLEN);
 
     sendingPacket = p;
-    return numbytes;
+    return p->encrypted.size + sizeof(PacketHeader);
 }

src/mesh/RadioLibInterface.cpp

@@ -289,20 +289,16 @@ void RadioLibInterface::handleReceiveInterrupt()
             } else {
                 MeshPacket *mp = packetPool.allocZeroed();
 
-                SubPacket *p = &mp->payload;
-
                 mp->from = h->from;
                 mp->to = h->to;
                 mp->id = h->id;
                 addReceiveMetadata(mp);
 
-                if (!pb_decode_from_bytes(payload, payloadLen, SubPacket_fields, p)) {
+                mp->which_payload = MeshPacket_encrypted_tag; // Mark that the payload is still encrypted at this point
-                    DEBUG_MSG("Invalid protobufs in received mesh packet, discarding.\n");
+                assert(payloadLen <= sizeof(mp->encrypted.bytes));
-                    packetPool.release(mp);
+                memcpy(mp->encrypted.bytes, payload, payloadLen);
-                    // rxBad++; not really a hw error
+                mp->encrypted.size = payloadLen;
-                } else {
+
-                    // parsing was successful, queue for our recipient
-                    mp->has_payload = true;
                 DEBUG_MSG("Lora RX interrupt from=0x%x, id=%u\n", mp->from, mp->id);
 
                 deliverToReceiver(mp);
@@ -310,7 +306,6 @@ void RadioLibInterface::handleReceiveInterrupt()
         }
     }
 }
-}
 
 /** start an immediate transmit */
 void RadioLibInterface::startSend(MeshPacket *txp)

src/mesh/Router.cpp

@@ -1,7 +1,11 @@
 #include "Router.h"
+#include "CryptoEngine.h"
+#include "GPS.h"
 #include "configuration.h"
 #include "mesh-pb-constants.h"
 
+CryptoEngine *crypto = new CryptoEngine();
+
 /**
  * Router todo
  *
@@ -48,6 +52,26 @@ void Router::loop()
  */
 ErrorCode Router::send(MeshPacket *p)
 {
+    // If the packet hasn't yet been encrypted, do so now (it might already be encrypted if we are just forwarding it)
+
+    assert(p->which_payload == MeshPacket_encrypted_tag ||
+           p->which_payload == MeshPacket_decoded_tag); // I _think_ all packets should have a payload by now
+
+    // First convert from protobufs to raw bytes
+    if (p->which_payload == MeshPacket_decoded_tag) {
+        static uint8_t bytes[MAX_RHPACKETLEN]; // we have to use a scratch buffer because a union
+
+        size_t numbytes = pb_encode_to_bytes(bytes, sizeof(bytes), SubPacket_fields, &p->decoded);
+
+        assert(numbytes <= MAX_RHPACKETLEN);
+        crypto->encrypt(p->from, p->id, numbytes, bytes);
+
+        // Copy back into the packet and set the variant type
+        memcpy(p->encrypted.bytes, bytes, numbytes);
+        p->encrypted.size = numbytes;
+        p->which_payload = MeshPacket_encrypted_tag;
+    }
+
     if (iface) {
         // DEBUG_MSG("Sending packet via interface fr=0x%x,to=0x%x,id=%d\n", p->from, p->to, p->id);
         return iface->send(p);
@@ -58,8 +82,6 @@ ErrorCode Router::send(MeshPacket *p)
     }
 }
 
-#include "GPS.h"
-
 /**
  * Handle any packet that is received by an interface on this node.
  * Note: some packets may merely being passed through this node and will be forwarded elsewhere.
@@ -70,7 +92,25 @@ void Router::handleReceived(MeshPacket *p)
     // Also, we should set the time from the ISR and it should have msec level resolution
     p->rx_time = getValidTime(); // store the arrival timestamp for the phone
 
+    assert(p->which_payload ==
+           MeshPacket_encrypted_tag); // I _think_ the only thing that pushes to us is raw devices that just received packets
+
+    // Try to decrypt the packet if we can
+    static uint8_t bytes[MAX_RHPACKETLEN];
+    memcpy(bytes, p->encrypted.bytes,
+           p->encrypted.size); // we have to copy into a scratch buffer, because these bytes are a union with the decoded protobuf
+    crypto->decrypt(p->from, p->id, p->encrypted.size, bytes);
+
+    // Take those raw bytes and convert them back into a well structured protobuf we can understand
+    if (!pb_decode_from_bytes(bytes, p->encrypted.size, SubPacket_fields, &p->decoded)) {
+        DEBUG_MSG("Invalid protobufs in received mesh packet, discarding.\n");
+    } else {
+        // parsing was successful, queue for our recipient
+        p->which_payload = MeshPacket_decoded_tag;
+
         DEBUG_MSG("Notifying observers of received packet fr=0x%x,to=0x%x,id=%d\n", p->from, p->to, p->id);
         notifyPacketReceived.notifyObservers(p);
+    }
+
     packetPool.release(p);
 }

src/mesh/mesh.pb.h

@@ -122,11 +122,15 @@ typedef struct _SubPacket {
     bool want_response;
 } SubPacket;
 
+typedef PB_BYTES_ARRAY_T(256) MeshPacket_encrypted_t;
 typedef struct _MeshPacket {
     int32_t from;
     int32_t to;
-    bool has_payload;
+    pb_size_t which_payload;
-    SubPacket payload;
+    union {
+        SubPacket decoded;
+        MeshPacket_encrypted_t encrypted;
+    };
     uint32_t rx_time;
     uint32_t id;
     float rx_snr;
@@ -193,7 +197,7 @@ typedef struct _ToRadio {
 #define User_init_default                        {"", "", "", {0}}
 #define RouteDiscovery_init_default              {{{NULL}, NULL}}
 #define SubPacket_init_default                   {false, Position_init_default, false, Data_init_default, false, User_init_default, 0}
-#define MeshPacket_init_default                  {0, 0, false, SubPacket_init_default, 0, 0, 0}
+#define MeshPacket_init_default                  {0, 0, 0, {SubPacket_init_default}, 0, 0, 0}
 #define ChannelSettings_init_default             {0, _ChannelSettings_ModemConfig_MIN, {0}, ""}
 #define RadioConfig_init_default                 {false, RadioConfig_UserPreferences_init_default, false, ChannelSettings_init_default}
 #define RadioConfig_UserPreferences_init_default {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}
@@ -208,7 +212,7 @@ typedef struct _ToRadio {
 #define User_init_zero                           {"", "", "", {0}}
 #define RouteDiscovery_init_zero                 {{{NULL}, NULL}}
 #define SubPacket_init_zero                      {false, Position_init_zero, false, Data_init_zero, false, User_init_zero, 0}
-#define MeshPacket_init_zero                     {0, 0, false, SubPacket_init_zero, 0, 0, 0}
+#define MeshPacket_init_zero                     {0, 0, 0, {SubPacket_init_zero}, 0, 0, 0}
 #define ChannelSettings_init_zero                {0, _ChannelSettings_ModemConfig_MIN, {0}, ""}
 #define RadioConfig_init_zero                    {false, RadioConfig_UserPreferences_init_zero, false, ChannelSettings_init_zero}
 #define RadioConfig_UserPreferences_init_zero    {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}
@@ -269,9 +273,10 @@ typedef struct _ToRadio {
 #define SubPacket_data_tag                       3
 #define SubPacket_user_tag                       4
 #define SubPacket_want_response_tag              5
+#define MeshPacket_decoded_tag                   3
+#define MeshPacket_encrypted_tag                 8
 #define MeshPacket_from_tag                      1
 #define MeshPacket_to_tag                        2
-#define MeshPacket_payload_tag                   3
 #define MeshPacket_rx_time_tag                   4
 #define MeshPacket_id_tag                        6
 #define MeshPacket_rx_snr_tag                    7
@@ -338,13 +343,14 @@ X(a, STATIC,   SINGULAR, BOOL,     want_response,     5)
 #define MeshPacket_FIELDLIST(X, a) \
 X(a, STATIC,   SINGULAR, INT32,    from,              1) \
 X(a, STATIC,   SINGULAR, INT32,    to,                2) \
-X(a, STATIC,   OPTIONAL, MESSAGE,  payload,           3) \
+X(a, STATIC,   ONEOF,    MESSAGE,  (payload,decoded,decoded),   3) \
+X(a, STATIC,   ONEOF,    BYTES,    (payload,encrypted,encrypted),   8) \
 X(a, STATIC,   SINGULAR, UINT32,   rx_time,           4) \
 X(a, STATIC,   SINGULAR, UINT32,   id,                6) \
 X(a, STATIC,   SINGULAR, FLOAT,    rx_snr,            7)
 #define MeshPacket_CALLBACK NULL
 #define MeshPacket_DEFAULT NULL
-#define MeshPacket_payload_MSGTYPE SubPacket
+#define MeshPacket_payload_decoded_MSGTYPE SubPacket
 
 #define ChannelSettings_FIELDLIST(X, a) \
 X(a, STATIC,   SINGULAR, INT32,    tx_power,          1) \

src/screen.cpp

@@ -81,7 +81,7 @@ static void drawTextMessageFrame(OLEDDisplay *display, OLEDDisplayUiState *state
     MeshPacket &mp = devicestate.rx_text_message;
     NodeInfo *node = nodeDB.getNode(mp.from);
     // DEBUG_MSG("drawing text message from 0x%x: %s\n", mp.from,
-    // mp.payload.variant.data.payload.bytes);
+    // mp.decoded.variant.data.decoded.bytes);
 
     // Demo for drawStringMaxWidth:
     // with the third parameter you can define the width after which words will
@@ -94,8 +94,8 @@ static void drawTextMessageFrame(OLEDDisplay *display, OLEDDisplayUiState *state
 
     // the max length of this buffer is much longer than we can possibly print
     static char tempBuf[96];
-    assert(mp.payload.has_data);
+    assert(mp.decoded.has_data);
-    snprintf(tempBuf, sizeof(tempBuf), "         %s", mp.payload.data.payload.bytes);
+    snprintf(tempBuf, sizeof(tempBuf), "         %s", mp.decoded.data.payload.bytes);
 
     display->drawStringMaxWidth(4 + x, 10 + y, 128, tempBuf);
 }