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Rewrite bt connection initiation sequence.
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@kareltucek
kareltucek committed Jan 5, 2025
1 parent c2aaf71 commit 7d95701
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Showing 3 changed files with 157 additions and 72 deletions.
203 changes: 135 additions & 68 deletions device/src/bt_conn.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -129,21 +129,31 @@ static void enableDataLengthExtension(struct bt_conn *conn) {
}
}

static void configureLatency(struct bt_conn *conn) {
// https://developer.apple.com/library/archive/qa/qa1931/_index.html
// https://punchthrough.com/manage-ble-connection/
// https://devzone.nordicsemi.com/f/nordic-q-a/28058/what-is-connection-parameters
static const struct bt_le_conn_param conn_params = BT_LE_CONN_PARAM_INIT(
6, 9, // keep it low, lowest allowed is 6 (7.5ms), lowest supported widely is 9 (11.25ms)
0, // keeping it higher allows power saving on peripheral when there's nothing to send (keep it under 30 though)
100 // connection timeout (*10ms)
);
int err = bt_conn_le_param_update(conn, &conn_params);
static void setLatency(struct bt_conn* conn, const struct bt_le_conn_param* params) {
int err = bt_conn_le_param_update(conn, params);
if (err) {
printk("LE latencies update failed: %d\n", err);
}
}

static void configureLatency(struct bt_conn *conn, latency_mode_t latencyMode) {
switch (latencyMode) {
case LatencyMode_NUS:
case LatencyMode_BleHid: {
// https://developer.apple.com/library/archive/qa/qa1931/_index.html
// https://punchthrough.com/manage-ble-connection/
// https://devzone.nordicsemi.com/f/nordic-q-a/28058/what-is-connection-parameters
const struct bt_le_conn_param conn_params = BT_LE_CONN_PARAM_INIT(
6, 9, // keep it low, lowest allowed is 6 (7.5ms), lowest supported widely is 9 (11.25ms)
0, // keeping it higher allows power saving on peripheral when there's nothing to send (keep it under 30 though)
100 // connection timeout (*10ms)
);
setLatency(conn, &conn_params);
}
break;
}
}

void BtConn_UpdateHostConnectionPeerAllocations() {
//for each peer
for (uint8_t peerId = PeerIdFirstHost; peerId <= PeerIdLastHost; peerId++) {
Expand Down Expand Up @@ -176,16 +186,17 @@ static uint8_t allocateHostPeer(uint8_t connectionType) {
return PeerIdUnknown;
}

static void assignPeer(struct bt_conn* conn, uint8_t connectionId, uint8_t connectionType) {
static uint8_t assignPeer(struct bt_conn* conn, uint8_t connectionId, uint8_t connectionType) {
bt_addr_le_t addr = *bt_conn_get_dst(conn);

// be idempotent
for (uint8_t i = PeerIdFirst; i < PeerCount; i++) {
if (Peers[i].conn == conn) {
Peers[i].addr = addr;
if (Peers[i].connectionId != connectionId) {
Connections_MoveConnection(i, Peers[i].connectionId, connectionId);
}
return;
return i;
}
}

Expand All @@ -194,14 +205,16 @@ static void assignPeer(struct bt_conn* conn, uint8_t connectionId, uint8_t conne
if (peerId == PeerIdUnknown) {
printk("No peer slot available for connection %d\n", connectionId);
bt_conn_disconnect(conn, BT_HCI_ERR_REMOTE_USER_TERM_CONN);
return;
return PeerIdUnknown;
}

Peers[peerId].conn = bt_conn_ref(conn);
Peers[peerId].addr = addr;
Peers[peerId].connectionId = connectionId;
Connections[connectionId].peerId = peerId;
Connections_SetState(connectionId, ConnectionState_Connected);

return peerId;
}

void bt_foreach_list_current_connections(struct bt_conn *conn, void *data)
Expand Down Expand Up @@ -241,43 +254,34 @@ static bool isWanted(struct bt_conn *conn, connection_type_t connectionType) {
}

static void connectNus(struct bt_conn *conn, connection_id_t connectionId, connection_type_t connectionType) {
int err;
uint8_t peerId = assignPeer(conn, connectionId, connectionType);

if ( !isWanted(conn, connectionType) ) {
printk("Refusing connenction %d (this is not a selected connection)\n", connectionId);
err = bt_conn_disconnect(conn, BT_HCI_ERR_REMOTE_USER_TERM_CONN);
return;
}
printf("Bt connected to %s\n", GetPeerStringByConn(conn));

assignPeer(conn, connectionId, connectionType);
configureLatency(conn, LatencyMode_NUS);
enableDataLengthExtension(conn);

printk("Bt connected to %s\n", GetPeerStringByConn(conn));
bt_conn_set_security(conn, BT_SECURITY_L4);
bool isRightClient = DEVICE_IS_UHK80_RIGHT && peerId == PeerIdLeft;
bool isDongleClient = DEVICE_IS_UHK_DONGLE && peerId == PeerIdRight;
if ( isRightClient || isDongleClient ) {
printk("Initiating NUS connection with %s\n", GetPeerStringByConn(conn));
NusClient_Connect(conn);
}
}

static void connectHid(struct bt_conn *conn, connection_id_t connectionId, connection_type_t connectionType) {
int err;
assignPeer(conn, connectionId, connectionType);

if ( !isWanted(conn, connectionType) ) {
printk("Refusing connenction %d (this is not a selected connection)\n", connectionId);
err = bt_conn_disconnect(conn, BT_HCI_ERR_REMOTE_USER_TERM_CONN);
return;
}
printf("Bt connected to %s\n", GetPeerStringByConn(conn));

static const struct bt_le_conn_param conn_params = BT_LE_CONN_PARAM_INIT(
6, 9, // keep it low, lowest allowed is 6 (7.5ms), lowest supported widely is 9 (11.25ms)
10, // keeping it higher allows power saving on peripheral when there's nothing to send (keep it under 30 though)
100 // connection timeout (*10ms)
);
bt_conn_le_param_update(conn, &conn_params);
configureLatency(conn, LatencyMode_NUS);

#if DEVICE_IS_UHK80_RIGHT
USB_DisableHid();
#endif

assignPeer(conn, connectionId, connectionType);

printk("Bt connected to %s\n", GetPeerStringByConn(conn));
// Assume that HOGP is ready
printf("Established HID connection with %s\n", GetPeerStringByConn(conn));
Connections_SetState(connectionId, ConnectionState_Ready);
}

Expand All @@ -287,8 +291,7 @@ static void connectHid(struct bt_conn *conn, connection_id_t connectionId, conne
ATTR_UNUSED static uint8_t discover_func(struct bt_conn *conn, const struct bt_gatt_attr *attr, struct bt_gatt_discover_params *params)
{
if (!attr) {
printk("Service discovery completed, connection wasn't matched.!\n");
// connectHid(conn, Connections_GetNewBtHidConnectionId(), ConnectionType_BtHid);
printk("Service discovery completed, connection wasn't matched. Requesting authentication!\n");
bt_conn_set_security(conn, BT_SECURITY_L4);
return BT_GATT_ITER_STOP;
}
Expand All @@ -309,7 +312,10 @@ ATTR_UNUSED static uint8_t discover_func(struct bt_conn *conn, const struct bt_g
return BT_GATT_ITER_CONTINUE;
}

static void connectedUnknown(struct bt_conn *conn) {
// check if the connection is NUS. If yes, disconnect it.
// Otherwise, assume that this is anonymous ble hid connection, and
// it to (try to) increase its security.
static void connectUnknown(struct bt_conn *conn) {
#if DEVICE_IS_UHK80_RIGHT || DEVICE_IS_UHK_DONGLE
int err;

Expand All @@ -330,44 +336,55 @@ static void connectedUnknown(struct bt_conn *conn) {
}

static void connected(struct bt_conn *conn, uint8_t err) {
if (err) {
printk("Failed to connect to %s, err %u\n", GetPeerStringByConn(conn), err);
BtManager_StartScanningAndAdvertising();
return;
}

{
const bt_addr_le_t * addr = bt_conn_get_dst(conn);
connection_id_t connectionId = Connections_GetConnectionIdByBtAddr(addr);
connection_type_t connectionType = Connections_Type(connectionId);

printk("connected %d %d\n", connectionId, connectionType);
const bt_addr_le_t * addr = bt_conn_get_dst(conn);
connection_id_t connectionId = Connections_GetConnectionIdByHostAddr(addr);
connection_type_t connectionType = Connections_Type(connectionId);

if (err) {
printk("Failed to connect to %s, err %u\n", GetPeerStringByConn(conn), err);
BtManager_StartScanningAndAdvertising();
return;
}
printk("connected %s, %d %d\n", GetPeerStringByConn(conn), connectionId, connectionType);

switch (connectionType) {
case ConnectionType_NusLeft:
case ConnectionType_NusRight:
case ConnectionType_NusDongle:
connectNus(conn, connectionId, connectionType);
break;
case ConnectionType_BtHid:
connectHid(conn, connectionId, connectionType);
break;
case ConnectionType_Unknown:
default:
connectedUnknown(conn);
break;
}
if (connectionId == ConnectionId_Invalid) {
connectUnknown(conn);
} else {

if (DEVICE_IS_UHK80_RIGHT) {
BtManager_StartScanningAndAdvertisingAsync();
if (isWanted(conn, connectionType)) {
bt_conn_set_security(conn, BT_SECURITY_L4);
} else {
printk("Refusing connenction %d (this is not a selected connection)\n", connectionId);
bt_conn_disconnect(conn, BT_HCI_ERR_REMOTE_USER_TERM_CONN);
}
}

BtManager_StartScanningAndAdvertisingAsync();


return;

/*
*+ switch (connectionType) {
+ case ConnectionType_NusLeft:
+ case ConnectionType_NusRight:
+ case ConnectionType_NusDongle:
+ connectNus(conn, connectionId, connectionType);
+ break;
+ case ConnectionType_BtHid:
+ connectHid(conn, connectionId, connectionType);
+ break;
+ case ConnectionType_Unknown:
+ default:
+ connectedUnknown(conn);
+ break;
+ }
+
+ if (DEVICE_IS_UHK80_RIGHT) {
+ BtManager_StartScanningAndAdvertising();
+ }
*/

/*
const bt_addr_le_t * addr = bt_conn_get_dst(conn);
Expand Down Expand Up @@ -489,6 +506,55 @@ static bool isUhkDeviceConnection(connection_type_t connectionType) {
}
}

static void connectAuthenticatedConnection(struct bt_conn *conn, connection_id_t connectionId, connection_type_t connectionType) {
// in case we don't have free connection slots and this is not the selected connection, then refuse
if (!isWanted(conn, connectionType)) {
printk("Refusing connenction %d (this is not a selected connection)\n", connectionId);
bt_conn_disconnect(conn, BT_HCI_ERR_REMOTE_USER_TERM_CONN);
return;
}

switch (connectionType) {
case ConnectionType_NusLeft:
case ConnectionType_NusRight:
case ConnectionType_NusDongle:
connectNus(conn, connectionId, connectionType);
break;
case ConnectionType_BtHid:
connectHid(conn, connectionId, connectionType);
break;
case ConnectionType_Unknown:
default:
printk("Authenticated connection is not known. Disconnecting %s", GetPeerStringByConn(conn));
bt_conn_disconnect(conn, BT_HCI_ERR_REMOTE_USER_TERM_CONN);
break;
}
}

static void securityChanged(struct bt_conn *conn, bt_security_t level, enum bt_security_err err) {
// In case of failure, disconnect
if (err || (level < BT_SECURITY_L4 && !Cfg.AllowUnsecuredConnections)) {
printk("Bt security failed: %s, level %u, err %d, disconnecting\n", GetPeerStringByConn(conn), level, err);
bt_conn_auth_cancel(conn);
return;
}


// Ignore connection that is being paired. At this point, the central is
// probably talking to us via an anonymous address, and it will yet change.
if (conn == auth_conn) {
printk("Bt connection secured: %s, level %u. It is auth_conn, so ignoring.\n", GetPeerStringByConn(conn), level);
return;
}

const bt_addr_le_t *addr = bt_conn_get_dst(conn);
connection_id_t connectionId = Connections_GetConnectionIdByHostAddr(addr);
connection_type_t connectionType = Connections_Type(connectionId);
connectAuthenticatedConnection(conn, connectionId, connectionType);
}


/*
static void securityChanged(struct bt_conn *conn, bt_security_t level, enum bt_security_err err) {
int8_t peerId = GetPeerIdByConn(conn);
uint8_t connectionId;
Expand Down Expand Up @@ -538,6 +604,7 @@ static void securityChanged(struct bt_conn *conn, bt_security_t level, enum bt_s
// gatt_discover(conn); // Taken from bt_central_uart.c
#endif
}
*/

__attribute__((unused)) static void infoLatencyParamsUpdated(struct bt_conn* conn, uint16_t interval, uint16_t latency, uint16_t timeout)
{
Expand Down Expand Up @@ -661,7 +728,7 @@ static void pairing_complete(struct bt_conn *conn, bool bonded) {
}

// we have to connect from here, because central changes its address *after* setting security
connectHid(conn, connectionId, connectionType);
connectAuthenticatedConnection(conn, connectionId, connectionType);
}


Expand Down
5 changes: 5 additions & 0 deletions device/src/bt_conn.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -43,6 +43,11 @@
uint32_t lastSwitchover;
} peer_t;

typedef enum {
LatencyMode_NUS,
LatencyMode_BleHid,
} latency_mode_t;

// Variables:

extern peer_t Peers[];
Expand Down
21 changes: 17 additions & 4 deletions device/src/connections.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -202,8 +202,9 @@ connection_target_t Connections_Target(connection_id_t connectionId) {
return ConnectionTarget_None;
}

static connection_id_t getConnIdByPeer(const bt_addr_le_t *addr) {
for (uint8_t peerId = 0; peerId < PeerCount; peerId++) {
static connection_id_t getConnIdByPeer(const bt_addr_le_t *addr, bool searchHosts) {
uint8_t stopAt = searchHosts ? PeerCount : PeerIdFirstHost;
for (uint8_t peerId = 0; peerId < stopAt; peerId++) {
bool addressMatches = BtAddrEq(addr, &Peers[peerId].addr);
bool isValidPeer = peerId < PeerIdFirstHost || Peers[peerId].conn;
if (addressMatches && isValidPeer) {
Expand Down Expand Up @@ -239,7 +240,7 @@ static connection_id_t getConnIdByAddr(const bt_addr_le_t *addr) {
connection_id_t Connections_GetConnectionIdByBtAddr(const bt_addr_le_t *addr) {
connection_id_t res = ConnectionId_Invalid;

res = getConnIdByPeer(addr);
res = getConnIdByPeer(addr, true);
if (res != ConnectionId_Invalid) {
return res;
}
Expand All @@ -253,7 +254,19 @@ connection_id_t Connections_GetConnectionIdByBtAddr(const bt_addr_le_t *addr) {
}

connection_id_t Connections_GetConnectionIdByHostAddr(const bt_addr_le_t *addr) {
return getConnIdByAddr(addr);
connection_id_t res = ConnectionId_Invalid;

res = getConnIdByPeer(addr, false);
if (res != ConnectionId_Invalid) {
return res;
}

res = getConnIdByAddr(addr);
if (res != ConnectionId_Invalid) {
return res;
}

return ConnectionId_Invalid;
}

connection_id_t Connections_GetNewBtHidConnectionId() {
Expand Down

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