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discover sends a single repeater discovery request and populates the neighbor list; self is excluded #1718

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liamcottle merged 4 commits into from
Feb 17, 2026
+56 −0
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discover sends a single repeater discovery request and populates the neighbor list; self is excluded #1718

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e8785dd
discover sends a single repeater discovery request and populates the …
Feb 16, 2026
87c78a9
discover.neighbors sends a tagged repeater discovery request and only…
Feb 17, 2026
bf9c6cb
Increased the timeout timer to 60 seconds, up from 30 seconds.
Feb 17, 2026
0770618
Allow repeater discovery even if repeater mode is disabled on the req…
Feb 17, 2026
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53 changes: 53 additions & 0 deletions examples/simple_repeater/MyMesh.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -738,6 +738,47 @@ void MyMesh::onControlDataRecv(mesh::Packet* packet) {
sendZeroHop(resp, getRetransmitDelay(resp)*4); // apply random delay (widened x4), as multiple nodes can respond to this
}
}
} else if (type == CTL_TYPE_NODE_DISCOVER_RESP && packet->payload_len >= 6) {
uint8_t node_type = packet->payload[0] & 0x0F;
if (node_type != ADV_TYPE_REPEATER) {
return;
}
if (packet->payload_len < 6 + PUB_KEY_SIZE) {
MESH_DEBUG_PRINTLN("onControlDataRecv: DISCOVER_RESP pubkey too short: %d", (uint32_t)packet->payload_len);
return;
}

if (pending_discover_tag == 0 || millisHasNowPassed(pending_discover_until)) {
pending_discover_tag = 0;
return;
}
uint32_t tag;
memcpy(&tag, &packet->payload[2], 4);
if (tag != pending_discover_tag) {
return;
}

mesh::Identity id(&packet->payload[6]);
if (id.matches(self_id)) {
return;
}
putNeighbour(id, rtc_clock.getCurrentTime(), packet->getSNR());
}
}

void MyMesh::sendNodeDiscoverReq() {
uint8_t data[10];
data[0] = CTL_TYPE_NODE_DISCOVER_REQ; // prefix_only=0
data[1] = (1 << ADV_TYPE_REPEATER);
getRNG()->random(&data[2], 4); // tag
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@ripplebiz ripplebiz Feb 17, 2026

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Should save the 4-byte tag to a member variable, then make sure the response packets match. Otherwise, a bad actor could pollute everyone's neighbors lists with random garbage.

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@liamcottle liamcottle Feb 17, 2026

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Possibly with a timeout too. So if the request tag is reused by some other nearby repeater in the future, it isn't using those responses as well. Probably unlikely since there's 4.2 billion combinations for a uint32_t tag, but if the member variable is never cleared, it's still another way to pollute, as anyone can listen to those tags as they go over the air.

memcpy(&pending_discover_tag, &data[2], 4);
pending_discover_until = futureMillis(60000);
uint32_t since = 0;
memcpy(&data[6], &since, 4);

auto pkt = createControlData(data, sizeof(data));
if (pkt) {
sendZeroHop(pkt);
}
}

Expand Down Expand Up @@ -801,6 +842,9 @@ MyMesh::MyMesh(mesh::MainBoard &board, mesh::Radio &radio, mesh::MillisecondCloc
_prefs.advert_loc_policy = ADVERT_LOC_PREFS;

_prefs.adc_multiplier = 0.0f; // 0.0f means use default board multiplier

pending_discover_tag = 0;
pending_discover_until = 0;
}

void MyMesh::begin(FILESYSTEM *fs) {
Expand Down Expand Up @@ -1168,6 +1212,15 @@ void MyMesh::handleCommand(uint32_t sender_timestamp, char *command, char *reply
} else {
strcpy(reply, "Err - ??");
}
} else if (memcmp(command, "discover.neighbors", 18) == 0) {
const char* sub = command + 18;
while (*sub == ' ') sub++;
if (*sub != 0) {
strcpy(reply, "Err - discover.neighbors has no options");
} else {
sendNodeDiscoverReq();
strcpy(reply, "OK - Discover sent");
}
} else{
_cli.handleCommand(sender_timestamp, command, reply); // common CLI commands
}
Expand Down
3 changes: 3 additions & 0 deletions examples/simple_repeater/MyMesh.h
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Original file line number Diff line number Diff line change
Expand Up @@ -97,6 +97,8 @@ class MyMesh : public mesh::Mesh, public CommonCLICallbacks {
RegionEntry* load_stack[8];
RegionEntry* recv_pkt_region;
RateLimiter discover_limiter, anon_limiter;
uint32_t pending_discover_tag;
unsigned long pending_discover_until;
bool region_load_active;
unsigned long dirty_contacts_expiry;
#if MAX_NEIGHBOURS
Expand All @@ -116,6 +118,7 @@ class MyMesh : public mesh::Mesh, public CommonCLICallbacks {
#endif

void putNeighbour(const mesh::Identity& id, uint32_t timestamp, float snr);
void sendNodeDiscoverReq();
uint8_t handleLoginReq(const mesh::Identity& sender, const uint8_t* secret, uint32_t sender_timestamp, const uint8_t* data, bool is_flood);
uint8_t handleAnonRegionsReq(const mesh::Identity& sender, uint32_t sender_timestamp, const uint8_t* data);
uint8_t handleAnonOwnerReq(const mesh::Identity& sender, uint32_t sender_timestamp, const uint8_t* data);
Expand Down