Initial checking of pairing tool

1 files changed, 995 insertions, 0 deletions

diff --git a/ltunify.c b/ltunify.c
new file mode 100644
index 0000000..aa19360
--- /dev/null
+++ b/ltunify.c
@@ -0,0 +1,995 @@
+/*
+ * Pair, unpair or list information about wireless devices like keyboards and
+ * mice that use the Logitech® Unifying receiver.
+ *
+ * Copyright (C) 2013 Peter Wu <lekensteyn@gmail.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <fcntl.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <string.h>
+#include <stdbool.h>
+#include <errno.h>
+#include <signal.h>
+#include <stdlib.h> /* strtoul */
+#include <stdint.h> /* uint16_t */
+#include <arpa/inet.h> /* ntohs, ntohl */
+
+// Set DEBUG envvar to enable printing extra verbose details
+static bool debug_enabled;
+
+typedef unsigned char u8;
+
+#define HEADER_SIZE		3
+#define SHORT_MESSAGE           0x10
+#define SHORT_MESSAGE_LEN       7
+#define LONG_MESSAGE            0x11
+#define LONG_MESSAGE_LEN        20
+
+#define DEVICE_RECEIVER         0xFF
+
+#define SUB_SET_REGISTER        0x80
+#define SUB_GET_REGISTER        0x81
+#define SUB_SET_LONG_REGISTER   0x82
+#define SUB_GET_LONG_REGISTER   0x83
+#define SUB_ERROR_MSG           0x8F
+
+#define NOTIF_DEV_DISCONNECT	0x40 /* Device Disconnection */
+#define NOTIF_DEV_CONNECT	0x41 /* Device Connection */
+#define NOTIF_RECV_LOCK_CHANGE	0x4A /* Unifying Receiver Locking Change information */
+
+#define REG_ENABLED_NOTIFS      0x00
+#define REG_CONNECTION_STATE    0x02
+/* Device Connection and Disconnection (Pairing) */
+#define REG_DEVICE_PAIRING      0xB2
+#define REG_DEVICE_ACTIVITY     0xB3
+#define REG_PAIRING_INFO        0xB5
+#define REG_VERSION_INFO	0xF1 /* undocumented */
+
+// Used for: {GET,SET}_REGISTER_{REQ,RSP}, SET_LONG_REGISTER_RSP, GET_LONG_REGISTER_REQ
+struct msg_short {
+        u8 address;
+        u8 value[3];
+};
+// Used for: SET_LONG_REGISTER_REQ, GET_LONG_REGISTER_RSP
+struct msg_long {
+        u8 address;
+        u8 str[16];
+};
+// Used for: ERROR_MSG
+struct msg_error {
+        u8 sub_id;
+        u8 address;
+        u8 error_code;
+        u8 padding; /* set to 0 */
+};
+
+// 0x00 Enable HID++ Notifications
+struct msg_enable_notifs {
+	u8 reporting_flags_devices; // bit 4 Battery status
+	u8 reporting_flags_receiver; // bit 0 Wireless noitifcations, 3 Software Present
+	u8 reporting_flags_receiver2; // (reserved)
+};
+
+// 0xB5 Pairing information, 0x20..0x2F - Unifying Device pairing information
+struct msg_dev_pair_info {
+	u8 requested_field; // 0x20..0x25
+	u8 dest_id;
+	u8 report_interval; // ms
+	u8 pid_msb;
+	u8 pid_lsb;
+	u8 _reserved1[2];
+	u8 device_type;
+	u8 _reserved2[6];
+};
+// 0xB5 Pairing information, 0x30..0x3F - Unifying Device extended pairing info
+struct msg_dev_ext_pair_info {
+	u8 requested_field; // 0x30..0x35
+	u8 serial_number[4]; // index 0 is MSB
+	u8 report_types[4]; // index 0 is MSB
+	u8 usability_info; // bits 0..3 is location of power switch
+};
+// 0xB5 Pairing information, 0x40..0x4F - Unifying Device name
+#define DEVICE_NAME_MAXLEN 14
+struct msg_dev_name {
+	u8 requested_field; // 0x40..0x45
+	u8 length;
+	char str[DEVICE_NAME_MAXLEN]; // UTF-8 encoding
+};
+
+struct notif_devcon {
+#define DEVCON_PROT_UNIFYING	0x04
+	u8 prot_type; // bits 0..2 is protocol type (4 for unifying), 3..7 is reserved
+#define DEVCON_DEV_TYPE_MASK	0x0f
+// Link status: 0 is established (in range), 1 is not established (out of range)
+#define DEVCON_LINK_STATUS_FLAG	0x40
+	u8 device_info;
+	// wireless product id:
+	u8 pid_lsb;
+	u8 pid_msb;
+};
+
+// Register 0x02 Connection State
+struct val_reg_connection_state {
+// 0x02 triggers a 0x41 notification for all known devices
+#define CONSTATE_ACTION_LIST_DEVICES	0x02
+	u8 action; // always 0 for read
+	u8 connected_devices_count;
+	u8 _undocumented2;
+};
+
+// Register 0xB2 Device Connection and Disconnection (Pairing)
+struct val_reg_devpair {
+#define DEVPAIR_KEEP_LOCK	0
+#define DEVPAIR_OPEN_LOCK	1
+#define DEVPAIR_CLOSE_LOCK	2
+#define DEVPAIR_DISCONNECT	3
+	u8 action;
+	u8 device_number; // same as device index from 0x41 notif
+	u8 open_lock_timeout; // timeout in seconds, 0 = default (30s)
+};
+
+// Register 0xF1 Version Info (undocumented)
+struct val_reg_version {
+// v1.v2.xxx
+#define VERSION_FIRMWARE	1
+// x.x.v1v2
+#define VERSION_FW_BUILD	2
+// value 3 is invalid for receiver, but returns 00 07 for keyboard
+// BL.v1.v2
+#define VERSION_BOOTLOADER	4
+	u8 select_field;
+	u8 v1;
+	u8 v2;
+};
+
+struct hidpp_message {
+        u8 report_id;
+        u8 device_index;
+        u8 sub_id;
+        union {
+                struct msg_short msg_short;
+                struct msg_long msg_long;
+                struct msg_error msg_error;
+        };
+};
+
+struct version {
+	u8 fw_major;
+	u8 fw_minor;
+	uint16_t fw_build;
+	u8 bl_major;
+	u8 bl_minor;
+};
+
+#define DEVICES_MAX	6u
+struct device {
+	bool device_present; // whether the device is paired
+	bool device_available; // whether the device is connected
+	u8 device_type;
+	uint16_t wireless_pid;
+	char name[DEVICE_NAME_MAXLEN + 1]; // include NUL byte
+	uint32_t serial_number;
+	u8 power_switch_location;
+	struct version version;
+};
+struct device devices[DEVICES_MAX];
+
+// error messages for type=8F (ERROR_MSG)
+static const char * error_messages[0xFF] = {
+	[0x01] = "SUCCESS",
+	[0x02] = "INVALID_SUBID",
+	[0x03] = "INVALID_ADDRESS",
+	[0x04] = "INVALID_VALUE",
+	[0x05] = "CONNECT_FAIL",
+	[0x06] = "TOO_MANY_DEVICES",
+	[0x07] = "ALREADY_EXISTS",
+	[0x08] = "BUSY",
+	[0x09] = "UNKNOWN_DEVICE",
+	[0x0a] = "RESOURCE_ERROR",
+	[0x0b] = "REQUEST_UNAVAILABLE",
+	[0x0c] = "INVALID_PARAM_VALUE",
+	[0x0d] = "WRONG_PIN_CODE",
+};
+
+static const char * device_type[0x0F] = {
+	[0x00] = "Unknown",
+	[0x01] = "Keyboard",
+	[0x02] = "Mouse",
+	[0x03] = "Numpad",
+	[0x04] = "Presenter",
+	// 0x05..0x07 Reserved for future
+	[0x08] = "Trackball",
+	[0x09] = "Touchpad",
+	// 0x0A..0x0F Reserved
+};
+
+const char *device_type_str(u8 type) {
+	if (type > 0x0F) {
+		return "(invalid)";
+	}
+	if (device_type[type]) {
+		return device_type[type];
+	}
+	return "(reserved)";
+}
+
+static void dump_msg(struct hidpp_message *msg, size_t payload_size, const char *tag) {
+	size_t i;
+
+	if (!debug_enabled) {
+		return;
+	}
+
+	// HACK: do not mess with stderr colors
+	fflush(NULL);
+	printf("\033[34m");
+	printf("%s: ", tag);
+	for (i=0; i<payload_size; i++) {
+		printf("%02x%c", ((char *) msg)[i] & 0xFF,
+				i + 1 == payload_size ? '\n' : ' ');
+	}
+	printf("\033[m");
+	fflush(NULL);
+}
+
+static ssize_t do_io(int fd, struct hidpp_message *msg, bool is_write) {
+        ssize_t r;
+        size_t payload_size = SHORT_MESSAGE_LEN;
+
+        if (msg->report_id == LONG_MESSAGE) {
+                payload_size = LONG_MESSAGE_LEN;
+        }
+
+	if (is_write) {
+		dump_msg(msg, payload_size, "wr");
+		r = write(fd, msg, payload_size);
+	} else {
+		r = read(fd, msg, payload_size);
+		if (r >= 0) {
+			int saved_errno = errno;
+			dump_msg(msg, r, "rd");
+			errno = saved_errno;
+		}
+	}
+        if ((size_t) r == payload_size
+		|| (msg->report_id == SUB_ERROR_MSG && r == SHORT_MESSAGE_LEN)) {
+		return payload_size;
+	}
+
+	if (r < 0) {
+		perror(is_write ? "write" : "read");
+	}
+	return 0;
+}
+static ssize_t do_read(int fd, struct hidpp_message *msg) {
+	return do_io(fd, msg, false);
+}
+static ssize_t do_write(int fd, struct hidpp_message *msg) {
+	return do_io(fd, msg, true);
+}
+
+const char *get_report_id_str(u8 report_type) {
+	switch (report_type) {
+	case SHORT_MESSAGE:
+		return "short";
+	case LONG_MESSAGE:
+		return "long";
+	default:
+		return "unkn";
+	}
+}
+
+bool process_notif_dev_connect(struct hidpp_message *msg, u8 *device_index,
+	bool *is_new_device) {
+	u8 dev_idx = msg->device_index;
+	struct notif_devcon *dcon = (struct notif_devcon *) &msg->msg_short;
+	struct device *dev;
+	if (msg->sub_id != NOTIF_DEV_CONNECT) {
+		fprintf(stderr, "Invalid msg type %#0x, expected dev conn notif\n",
+			msg->sub_id);
+		return false;
+	}
+	if (msg->report_id != SHORT_MESSAGE) {
+		fprintf(stderr, "Dev conn notif is exoected to be short, got "
+			"%#04x instead\n", msg->report_id);
+		return false;
+	}
+	if (dcon->prot_type != DEVCON_PROT_UNIFYING) {
+		fprintf(stderr, "Unknown protocol %#04x in devcon notif\n",
+			dcon->prot_type);
+		return false;
+	}
+	if (dev_idx < 1 || dev_idx > DEVICES_MAX) {
+		fprintf(stderr, "Disallowed device index %#04x\n", dev_idx);
+		return false;
+	}
+
+	dev = &devices[dev_idx - 1];
+	if (device_index) *device_index = dev_idx;
+	if (is_new_device) *is_new_device = !dev->device_present;
+
+	memset(&devices[dev_idx], 0, sizeof devices[dev_idx]);
+	dev->device_type = dcon->device_info & DEVCON_DEV_TYPE_MASK;
+	dev->wireless_pid = (dcon->pid_msb << 8) | dcon->pid_lsb;
+	dev->device_present = true;
+	dev->device_available = !(dcon->device_info & DEVCON_LINK_STATUS_FLAG);
+	return true;
+}
+
+// use for reading registers and skipping notifications from return
+static bool do_read_skippy(int fd, struct hidpp_message *msg,
+	u8 exp_report_id, u8 exp_sub_id) {
+	for (;;) {
+		msg->report_id = exp_report_id;
+		if (!do_read(fd, msg)) {
+			return false;
+		}
+		if (msg->report_id == exp_report_id && msg->sub_id == exp_sub_id) {
+			return true;
+		}
+		if (msg->report_id == SHORT_MESSAGE && msg->sub_id == SUB_ERROR_MSG
+			&& msg->msg_error.sub_id == exp_sub_id) {
+			struct msg_error *error = &msg->msg_error;
+			// TODO: consider address (register)?
+			u8 error_code = error->error_code;
+			const char *err_str = error_messages[error_code];
+			if (debug_enabled) {
+				fprintf(stderr, "Received error for subid=%#04x,"
+					" reg=%#04x: %#04x (%s)\n", error->sub_id,
+					error->address, error_code, err_str);
+			}
+			return false;
+		}
+		if (msg->sub_id == NOTIF_DEV_CONNECT) {
+			process_notif_dev_connect(msg, NULL, NULL);
+			continue;
+		} else if (msg->sub_id == NOTIF_DEV_DISCONNECT) {
+			u8 device_index = msg->device_index;
+			u8 disconnect_type = *(u8 *) &msg->msg_short;
+			if (device_index < 1 || device_index > DEVICES_MAX) {
+				fprintf(stderr, "Invalid device index %#04x\n", device_index);
+			} else if (disconnect_type & 0x02) {
+				memset(&devices[device_index - 1], 0, sizeof *devices);
+			} else {
+				fprintf(stderr, "Unexpected disconnection type %#04x\n", disconnect_type);
+			}
+		} else if (msg->sub_id == NOTIF_RECV_LOCK_CHANGE) {
+			if (msg->report_id != SHORT_MESSAGE || msg->device_index != DEVICE_RECEIVER) {
+				fprintf(stderr, "Received invalid Unifying Receiver Locking Change notification (0x4A)\n");
+				continue;
+			}
+			// TODO: this can be used to make an application aware
+			// that pairing is (not) possible (anymore)
+			if (debug_enabled) {
+				fprintf(stderr, "Receiver lock state is now %s\n",
+					(*(u8 *)&msg->msg_short) & 1 ? "open" : "closed");
+			}
+		}
+		if (debug_enabled &&
+			(msg->report_id != exp_report_id || msg->sub_id != exp_sub_id)) {
+			fprintf(stderr, "Expected %s msg %#02x, got %s msg %#02x\n",
+				get_report_id_str(exp_report_id), exp_sub_id,
+				get_report_id_str(msg->report_id), msg->sub_id);
+		}
+		// let's try reading another message...
+	}
+	return true;
+}
+
+static bool set_register(int fd, u8 device_index, u8 address,
+	u8 *params, struct hidpp_message *res, bool is_long_req) {
+	u8 exp_sub_id;
+        struct hidpp_message msg;
+
+        msg.device_index = device_index;
+	if (is_long_req) {
+		msg.report_id = LONG_MESSAGE;
+		exp_sub_id = SUB_SET_LONG_REGISTER;
+		msg.msg_long.address = address;
+		memcpy(&msg.msg_long.str, params, LONG_MESSAGE_LEN - HEADER_SIZE);
+	} else {
+		msg.report_id = SHORT_MESSAGE;
+		exp_sub_id = SUB_SET_REGISTER;
+		msg.msg_short.address = address;
+		memcpy(&msg.msg_short.value, params, SHORT_MESSAGE_LEN - HEADER_SIZE);
+	}
+	msg.sub_id = exp_sub_id;
+
+        if (!do_write(fd, &msg)) {
+                return false;
+        }
+
+        msg.report_id = SHORT_MESSAGE;
+        if (!do_read_skippy(fd, &msg, SHORT_MESSAGE, exp_sub_id)) {
+                return false;
+        }
+        memcpy(res, &msg, sizeof msg);
+        return true;
+}
+
+bool set_short_register(int fd, u8 device_index, u8 address, u8 *params, struct hidpp_message *res) {
+        return set_register(fd, device_index, address, params, res, false);
+}
+bool set_long_register(int fd, u8 device_index, u8 address, u8 *params, struct hidpp_message *res) {
+	return set_register(fd, device_index, address, params, res, true);
+}
+
+static bool get_register(int fd, u8 device_index, u8 address,
+	struct hidpp_message *out, u8 *params, bool is_long_resp) {
+	u8 exp_report_id, exp_sub_id;
+        struct hidpp_message msg;
+
+	exp_report_id = is_long_resp ? LONG_MESSAGE : SHORT_MESSAGE;
+	exp_sub_id = is_long_resp ? SUB_GET_LONG_REGISTER : SUB_GET_REGISTER;
+
+        msg.report_id = SHORT_MESSAGE;
+        msg.device_index = device_index;
+        msg.sub_id = exp_sub_id;
+        memset(msg.msg_short.value, 0, sizeof msg.msg_short.value);
+	msg.msg_short.address = address;
+	if (params) {
+		memcpy(&msg.msg_short.value, params, SHORT_MESSAGE_LEN - HEADER_SIZE);
+	}
+
+        if (!do_write(fd, &msg)) {
+                return false;
+        }
+
+        if (!do_read_skippy(fd, &msg, exp_report_id, exp_sub_id)) {
+                return false;
+	}
+        memcpy(out, &msg, sizeof msg);
+        return true;
+}
+
+bool get_short_register(int fd, u8 device_index, u8 address, u8 *params, struct hidpp_message *out) {
+	return get_register(fd, device_index, address, out, params, false);
+}
+bool get_long_register(int fd, u8 device_index, u8 address, u8 *params, struct hidpp_message *out) {
+	return get_register(fd, device_index, address, out, params, true);
+}
+
+bool get_info(int fd, struct hidpp_message *msg) {
+        if (!get_long_register(fd, DEVICE_RECEIVER, REG_DEVICE_ACTIVITY, NULL, msg)) {
+                return false;
+        }
+        return true;
+}
+
+// begin directly-usable functions
+bool get_notifications(int fd, u8 device_index, struct msg_enable_notifs *params) {
+	struct hidpp_message msg;
+        if (!get_short_register(fd, device_index, REG_ENABLED_NOTIFS, NULL, &msg)) {
+                return false;
+        }
+	memcpy((u8 *) params, &msg.msg_short.value, sizeof *params);
+        return true;
+}
+bool set_notifications(int fd, u8 device_index, struct msg_enable_notifs *params) {
+	struct hidpp_message msg;
+        if (!set_short_register(fd, device_index, REG_ENABLED_NOTIFS, (u8 *) params, &msg)) {
+                return false;
+        }
+        return true;
+}
+bool get_and_print_notifications(int fd, u8 device_index, struct msg_enable_notifs *notifsp) {
+	putchar('\n');
+	if (get_notifications(fd, device_index, notifsp)) {
+		u8 flags = notifsp->reporting_flags_receiver;
+		printf("Reporting Flags (Receiver) = %02x\n", flags & 0xFF);
+		printf("Wireless notifications     = %s\n", flags & 1 ? "yes" : "no");
+		printf("Software Present           = %s\n", flags & 4 ? "yes" : "no");
+		return true;
+	} else {
+		fprintf(stderr, "Failed to get HID++ Notification status\n");
+		return false;
+	}
+}
+
+bool get_connected_devices(int fd, u8 *devices_count) {
+	struct hidpp_message msg;
+	struct val_reg_connection_state *cval;
+	if (!get_short_register(fd, DEVICE_RECEIVER, REG_CONNECTION_STATE, NULL, &msg)) {
+		return false;
+	}
+	cval = (struct val_reg_connection_state *) msg.msg_short.value;
+	*devices_count = cval->connected_devices_count;
+	return true;
+}
+
+bool pair_start(int fd, u8 timeout) {
+	struct hidpp_message msg;
+	struct val_reg_devpair cmd;
+	cmd.action = DEVPAIR_OPEN_LOCK;
+	// device_index is 1..6 for a specific device, 0x53 is seen for "any
+	// device".  Not sure if this is a special value or randomly chosen
+	cmd.device_number = 0;
+	cmd.open_lock_timeout = timeout;
+	if (!set_short_register(fd, DEVICE_RECEIVER, REG_DEVICE_PAIRING, (u8 *) &cmd, &msg)) {
+		return false;
+	}
+	return true;
+}
+
+bool pair_cancel(int fd) {
+	struct hidpp_message msg;
+	struct val_reg_devpair cmd;
+	cmd.action = DEVPAIR_CLOSE_LOCK;
+	// see discussion at pair_start, why did logitech use 0x53? Confusion?
+	cmd.device_number = 0;
+	// timeout applies to open lock, not sure why I saw 0x94 (148 sec)
+	cmd.open_lock_timeout = 0;
+	if (!set_short_register(fd, DEVICE_RECEIVER, REG_DEVICE_PAIRING, (u8 *) &cmd, &msg)) {
+		return false;
+	}
+	return true;
+}
+
+bool device_unpair(int fd, u8 device_index) {
+	struct hidpp_message msg;
+	struct val_reg_devpair cmd;
+	cmd.action = DEVPAIR_DISCONNECT;
+	cmd.device_number = device_index;
+	cmd.open_lock_timeout = 0;
+	if (!set_short_register(fd, DEVICE_RECEIVER, REG_DEVICE_PAIRING, (u8 *) &cmd, &msg)) {
+		return false;
+	}
+	return true;
+}
+
+void perform_pair(int fd, u8 timeout) {
+	struct hidpp_message msg;
+	if (!pair_start(fd, timeout)) {
+		fprintf(stderr, "Failed to send pair request\n");
+		return;
+	}
+	// WARNING: mess ahead. I knew it would become messy before writing it.
+	for (;;) {
+		msg.report_id = SHORT_MESSAGE;
+		if (!do_read(fd, &msg)) {
+			fprintf(stderr, "Failed to read short message\n");
+			break;
+		}
+		if (msg.sub_id == NOTIF_RECV_LOCK_CHANGE) {
+			u8 *bytes = (u8 *) &msg.msg_short;
+			if (msg.report_id != SHORT_MESSAGE || msg.device_index != DEVICE_RECEIVER) {
+				fprintf(stderr, "Received invalid Unifying Receiver Locking Change notification (0x4A)\n");
+				continue;
+			}
+			if (bytes[0] & 1) { // locking open
+				continue;
+			} else { // locking closed
+				const char *result;
+				switch (bytes[1]) {
+				case 0x00:
+					result = "Success";
+					break;
+				case 0x01:
+					result = "Timeout";
+					break;
+				default:
+					result = "Failure";
+				}
+				printf("Pairing result: %s (%i)\n", result, bytes[1]);
+				break;
+			}
+		} else if (msg.sub_id == NOTIF_DEV_CONNECT) {
+			u8 device_index;
+			bool is_new_dev;
+			if (!process_notif_dev_connect(&msg, &device_index, &is_new_dev)) {
+				// error message is already emitted
+				continue;
+			}
+
+			if (device_index < 1 || device_index > DEVICES_MAX) {
+				fprintf(stderr, "Invalid device index %#04x\n", device_index);
+			} else if (is_new_dev) {
+				u8 device_type = devices[device_index - 1].device_type;
+				printf("Found new device, id=%#04x %s\n",
+					device_index,
+					device_type_str(device_type));
+				break;
+			} else {
+				printf("Ignoring existent device id=%#04x\n", device_index);
+			}
+		}
+	}
+	// end of mess
+	if (!pair_cancel(fd)) {
+		fprintf(stderr, "Failed to cancel pair visibility\n");
+	}
+}
+void perform_unpair(int fd, u8 device_index) {
+	struct device *dev = &devices[device_index - 1];
+	if (!dev->device_present) {
+		printf("Device %#04x does not appear to be paired\n", device_index);
+		return;
+	}
+	if (device_unpair(fd, device_index)) {
+		if (!dev->device_present) {
+			printf("Device %#04x succesfully unpaired\n", device_index);
+		} else {
+			fprintf(stderr, "Unpairing of %#04x possibly failed\n", device_index);
+		}
+	} else {
+		fprintf(stderr, "Failed to send unpair %#04x request\n", device_index);
+	}
+}
+
+// triggers a notification that updates the list of paired devices
+bool get_all_devices(int fd) {
+	struct hidpp_message msg;
+	struct val_reg_connection_state cval;
+	memset(&cval, 0, sizeof cval);
+	cval.action = CONSTATE_ACTION_LIST_DEVICES;
+	if (!set_short_register(fd, DEVICE_RECEIVER, REG_CONNECTION_STATE, (u8 *) &cval, &msg)) {
+		return false;
+	}
+	return true;
+}
+bool get_device_pair_info(int fd, u8 device_index) {
+	struct device *dev = &devices[device_index - 1];
+	struct hidpp_message msg;
+	u8 params[3] = {0};
+
+	params[0] = 0x20 | (device_index - 1); // 0x20..0x2F Unifying Device pairing info
+	if (get_long_register(fd, DEVICE_RECEIVER, REG_PAIRING_INFO, params, &msg)) {
+		struct msg_dev_pair_info *info = (struct msg_dev_pair_info *) &msg.msg_long.str;
+
+		dev->wireless_pid = (info->pid_msb << 8) | info->pid_lsb;
+		dev->device_type = info->device_type;
+		return true;
+	}
+	return false;
+}
+bool get_device_ext_pair_info(int fd, u8 device_index) {
+	struct device *dev = &devices[device_index - 1];
+	struct hidpp_message msg;
+	u8 params[3] = {0};
+
+	params[0] = 0x30 | (device_index - 1); // 0x30..0x3F Unifying Device extended pairing info
+	if (get_long_register(fd, DEVICE_RECEIVER, REG_PAIRING_INFO, params, &msg)) {
+		struct msg_dev_ext_pair_info *info;
+		uint32_t *serial_numberp;
+
+		info = (struct msg_dev_ext_pair_info *) &msg.msg_long.str;
+		serial_numberp = (uint32_t *) &info->serial_number;
+
+		dev->serial_number = ntohl(*serial_numberp);
+		dev->power_switch_location = info->usability_info & 0x0F;
+		return true;
+	}
+	return false;
+}
+bool get_device_name(int fd, u8 device_index) {
+	struct device *dev = &devices[device_index - 1];
+	struct hidpp_message msg;
+	u8 params[3] = {0};
+
+	params[0] = 0x40 | (device_index - 1); // 0x40..0x4F Unifying Device Name
+	if (get_long_register(fd, DEVICE_RECEIVER, REG_PAIRING_INFO, params, &msg)) {
+		struct msg_dev_name *name = (struct msg_dev_name *) &msg.msg_long.str;
+		if (name->length > DEVICE_NAME_MAXLEN) {
+			fprintf(stderr, "Invalid name length %#04x for idx=%i\n", name->length, device_index);
+			return false;
+		}
+
+		memcpy(&dev->name, name->str, name->length);
+		dev->name[name->length] = 0;
+		return true;
+	}
+	return false;
+}
+
+// device_index can also be 0xFF for receiver
+bool get_device_version(int fd, u8 device_index, u8 version_type, struct val_reg_version *ver) {
+	struct hidpp_message msg;
+	// TODO: not 100% reliable for wireless devices, it may return MSG_ERR
+	// (err=SUCCESS, wtf). Perhaps we need to send another msg type=00
+	// (whatever the undocumened params are).
+
+	memset(ver, 0, sizeof *ver);
+	ver->select_field = version_type;
+	if (get_short_register(fd, device_index, REG_VERSION_INFO, (u8 *) ver, &msg)) {
+		memcpy(ver, msg.msg_short.value, sizeof *ver);
+		return true;
+	}
+	return false;
+}
+
+bool get_device_versions(int fd, u8 device_index, struct version *version) {
+	struct val_reg_version ver;
+
+	if (get_device_version(fd, device_index, VERSION_FIRMWARE, &ver)) {
+		version->fw_major = ver.v1;
+		version->fw_minor = ver.v2;
+	} else {
+		// assume that other versions will fail too
+		return false;
+	}
+	if (get_device_version(fd, device_index, VERSION_FW_BUILD, &ver)) {
+		version->fw_build = (ver.v1 << 8) | ver.v2;
+	}
+	//if (get_device_version(fd, device_index, 3, &ver)) puts("No idea what this is useful for");
+	if (get_device_version(fd, device_index, VERSION_BOOTLOADER, &ver)) {
+		version->bl_major = ver.v1;
+		version->bl_minor = ver.v2;
+	}
+	return true;
+}
+
+// device index is 1..6
+void gather_device_info(int fd, u8 device_index) {
+	if (get_device_pair_info(fd, device_index)) {
+		struct device *dev = &devices[device_index - 1];
+
+		dev->device_present = true;
+
+		get_device_ext_pair_info(fd, device_index);
+		get_device_name(fd, device_index);
+		if (get_device_versions(fd, device_index, &dev->version)) {
+			dev->device_available = true;
+		}
+	} else {
+		// retrieve some information from notifier
+		get_all_devices(fd);
+	}
+}
+
+void print_versions(struct version *ver) {
+	// versions are shown as hex. Probably a mistake given that the length
+	// is 3 which can fit 255 instead of FF (and 65535 instead of FF)
+	printf("Firmware version: %03x.%03x.%05x\n",
+			ver->fw_major, ver->fw_minor, ver->fw_build);
+	printf("Bootloader version: BL.%03x.%03x\n",
+			ver->bl_major, ver->bl_minor);
+}
+
+void get_and_print_recv_fw(int fd) {
+	struct version version;
+
+	if (get_device_versions(fd, DEVICE_RECEIVER, &version)) {
+		print_versions(&version);
+		putchar('\n');
+	}
+}
+
+void print_detailed_device(u8 device_index) {
+	struct device *dev = &devices[device_index - 1];
+
+	if (!dev->device_present) {
+		printf("Device %i is not paired\n", device_index);
+		return;
+	}
+
+	printf("Device index %i\n", device_index);
+	printf("%s\n", device_type_str(dev->device_type));
+	printf("Name: %s\n", dev->name);
+	printf("Wireless Product ID: %04X\n", dev->wireless_pid);
+	printf("Serial number: %08X\n", dev->serial_number);
+	if (dev->device_available) {
+		print_versions(&dev->version);
+	} else {
+		puts("Device was unavailable, version information not available.");
+	}
+}
+void get_device_names(int fd) {
+	u8 i;
+
+	for (i=0; i<DEVICES_MAX; i++) {
+		struct device *dev = &devices[i];
+		if (!dev->device_present) {
+			continue;
+		}
+
+		if (!get_device_name(fd, i + 1)) {
+			fprintf(stderr, "Failed to read device name for idx=%i\n", i + 1);
+		}
+	}
+}
+void print_all_devices(void) {
+	unsigned i;
+	puts("Connected devices:");
+	for (i=0; i<DEVICES_MAX; i++) {
+		struct device *dev = &devices[i];
+		if (!dev->device_present) {
+			continue;
+		}
+
+		printf("idx=%i\t%s\t%s\n", i + 1,
+			device_type_str(dev->device_type), dev->name);
+	}
+}
+
+// begin signal functions
+static bool stopping;
+static void sig_handler(int signum) {
+	if (signum != SIGINT) {
+		return;
+	}
+	fprintf(stderr, "Caught SIGINT, shutting down\n");
+	stopping = true;
+}
+static void install_sighandlers(void) {
+	struct sigaction sa;
+	memset(&sa, 0, sizeof sa);
+	sa.sa_handler = sig_handler;
+	sigaction(SIGINT, &sa, NULL);
+}
+// end signal functions
+
+static void print_usage(const char *program_name) {
+	fprintf(stderr, "Usage: %s /dev/hidrawX cmd [cmd options]\n"
+"Logitech Unifying tool\n"
+"Copyright (C) 2013 Peter Wu <lekensteyn@gmail.com>\n"
+"\n"
+"Commands:\n"
+"  list            - show all paired devices\n"
+"  pair [timeout]  - Try to pair within \"timeout\" seconds (1 to 255,\n"
+"                    default 0 which is an alias for 30s)\n"
+"  unpair idx      - Unpair device\n"
+"  info idx        - Show more detailled information for a device\n"
+"In the above lines, \"idx\" refers to the device number shown in the\n"
+" first column of the list command (between 1 and 6).\n"
+	, program_name);
+}
+
+static bool validate_args(int argc, char **argv) {
+	char *cmd;
+
+	if (argc < 3) {
+		return false;
+	}
+
+	cmd = argv[2];
+	if (!strcmp(cmd, "list")) {
+		return true;
+	} else if (!strcmp(cmd, "pair")) {
+		// timeout is optional, do not check
+		return true;
+	} else if (!strcmp(cmd, "unpair") || !strcmp(cmd, "info")) {
+		u8 device_index;
+		if (argc < 4) {
+			return false;
+		}
+		device_index = (u8) strtoul(argv[3], NULL, 0);
+		if (device_index < 1 || device_index > DEVICES_MAX) {
+			fprintf(stderr, "Device index must be between 1 and 6.\n");
+			return false;
+		}
+		return true;
+	}
+
+	// unrecognized command
+	return false;
+}
+
+int main(int argc, char **argv) {
+        int fd;
+	struct msg_enable_notifs notifs;
+	char *cmd;
+
+	debug_enabled = !!getenv("DEBUG");
+
+        if (!validate_args(argc, argv)) {
+		print_usage(*argv);
+		return 1;
+        }
+	cmd = argv[2];
+
+        fd = open(argv[1], O_RDWR);
+        if (fd < 0) {
+                perror(argv[1]);
+                return 1;
+        }
+
+	if (debug_enabled) {
+		if (!get_and_print_notifications(fd, DEVICE_RECEIVER, &notifs)) {
+			goto end_close;
+		}
+	} else {
+		if (!get_notifications(fd, DEVICE_RECEIVER, &notifs)) {
+			fprintf(stderr, "Failed to retrieve notification state\n");
+			goto end_close;
+		}
+	}
+
+	install_sighandlers();
+
+	notifs.reporting_flags_receiver |= 1;
+	if (set_notifications(fd, DEVICE_RECEIVER, &notifs)) {
+		if (debug_enabled) {
+			puts("Succesfully enabled notifications");
+		}
+	} else {
+		fprintf(stderr, "Failed to set HID++ Notification status\n");
+	}
+
+	if (!strcmp(cmd, "pair")) {
+		u8 timeout = 0;
+		if (argc >= 4) {
+			timeout = (u8) strtoul(argv[3], NULL, 0);
+		}
+		perform_pair(fd, timeout);
+	} else if (!strcmp(cmd, "unpair")) {
+		u8 device_index;
+		device_index = (u8) strtoul(argv[3], NULL, 0);
+		if (!get_all_devices(fd)) {
+			fprintf(stderr, "Unable to request a list of paired devices\n");
+		}
+		perform_unpair(fd, device_index);
+	} else if (!strcmp(cmd, "list")) {
+		u8 device_count;
+		if (get_connected_devices(fd, &device_count)) {
+			printf("Devices count: %i\n", device_count);
+		} else {
+			fprintf(stderr, "Failed to get connected devices count\n");
+		}
+
+		if (get_all_devices(fd)) {
+			get_device_names(fd);
+			print_all_devices();
+		} else {
+			fprintf(stderr, "Unable to request a list of paired devices\n");
+		}
+	} else if (!strcmp(cmd, "info")) {
+		u8 device_index;
+
+		get_and_print_recv_fw(fd);
+
+		device_index = (u8) strtoul(argv[3], NULL, 0);
+		gather_device_info(fd, device_index);
+		print_detailed_device(device_index);
+	} else {
+		print_usage(*argv);
+		goto end_notifs;
+	}
+
+#if 0
+        struct hidpp_message msg;
+        while (!stopping && get_info(fd, &msg)) {
+                u8 *resp = msg.msg_long.str;
+                unsigned i;
+		// activity counter for each device
+                for (i=0; i<DEVICES_MAX; i++) {
+                        printf("%2x%c", resp[i], i == 5 ? '\n' : ' ');
+                }
+                usleep(100000);
+		getchar();
+        }
+#endif
+
+end_notifs:
+	notifs.reporting_flags_receiver &= ~1;
+	if (set_notifications(fd, DEVICE_RECEIVER, &notifs)) {
+		if (debug_enabled) {
+			puts("Succesfully disabled notifications");
+		}
+	} else {
+		fprintf(stderr, "Failed to set HID++ Notification status\n");
+	}
+
+	if (debug_enabled) {
+		get_and_print_notifications(fd, DEVICE_RECEIVER, &notifs);
+	}
+
+end_close:
+        close(fd);
+
+        return 0;
+}