From 57da37cfbca4ef5b47c346e4f2de02d00f33a726 Mon Sep 17 00:00:00 2001 From: Ben Meadors Date: Wed, 1 May 2024 08:05:26 -0500 Subject: [PATCH] Position module should enforce precision for phone originated position packets (#3752) --- src/modules/PositionModule.cpp | 17 +++++++++++++++++ src/modules/PositionModule.h | 2 ++ 2 files changed, 19 insertions(+) diff --git a/src/modules/PositionModule.cpp b/src/modules/PositionModule.cpp index 658b8b5a7..7c459dc35 100644 --- a/src/modules/PositionModule.cpp +++ b/src/modules/PositionModule.cpp @@ -87,6 +87,23 @@ bool PositionModule::handleReceivedProtobuf(const meshtastic_MeshPacket &mp, mes return false; // Let others look at this message also if they want } +void PositionModule::alterReceivedProtobuf(meshtastic_MeshPacket &mp, meshtastic_Position *p) +{ + // Phone position packets need to be truncated to the channel precision + if (nodeDB->getNodeNum() == getFrom(&mp) && (precision < 32 && precision > 0)) { + LOG_DEBUG("Truncating phone position to channel precision %i\n", precision); + p->latitude_i = p->latitude_i & (UINT32_MAX << (32 - precision)); + p->longitude_i = p->longitude_i & (UINT32_MAX << (32 - precision)); + + // We want the imprecise position to be the middle of the possible location, not + p->latitude_i += (1 << (31 - precision)); + p->longitude_i += (1 << (31 - precision)); + + mp.decoded.payload.size = + pb_encode_to_bytes(mp.decoded.payload.bytes, sizeof(mp.decoded.payload.bytes), &meshtastic_Position_msg, p); + } +} + void PositionModule::trySetRtc(meshtastic_Position p, bool isLocal) { struct timeval tv; diff --git a/src/modules/PositionModule.h b/src/modules/PositionModule.h index 89ff50c64..1161159f7 100644 --- a/src/modules/PositionModule.h +++ b/src/modules/PositionModule.h @@ -42,6 +42,8 @@ class PositionModule : public ProtobufModule, private concu */ virtual bool handleReceivedProtobuf(const meshtastic_MeshPacket &mp, meshtastic_Position *p) override; + virtual void alterReceivedProtobuf(meshtastic_MeshPacket &mp, meshtastic_Position *p) override; + /** Messages can be received that have the want_response bit set. If set, this callback will be invoked * so that subclasses can (optionally) send a response back to the original sender. */ virtual meshtastic_MeshPacket *allocReply() override;