WIP: totp watch face read from file

movement/lib/base32/base32.c

@@ -0,0 +1,221 @@
+/**
+ * base32 (de)coder implementation as specified by RFC4648.
+ *
+ * Copyright (c) 2010 Adrien Kunysz
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ **/
+
+#include <assert.h>  // assert()
+#include <limits.h>  // CHAR_BIT
+
+#include "base32.h"
+
+/**
+ * Let this be a sequence of plain data before encoding:
+ *
+ *  01234567 01234567 01234567 01234567 01234567
+ * +--------+--------+--------+--------+--------+
+ * |< 0 >< 1| >< 2 ><|.3 >< 4.|>< 5 ><.|6 >< 7 >|
+ * +--------+--------+--------+--------+--------+
+ *
+ * There are 5 octets of 8 bits each in each sequence.
+ * There are 8 blocks of 5 bits each in each sequence.
+ *
+ * You probably want to refer to that graph when reading the algorithms in this
+ * file. We use "octet" instead of "byte" intentionnaly as we really work with
+ * 8 bits quantities. This implementation will probably not work properly on
+ * systems that don't have exactly 8 bits per (unsigned) char.
+ **/
+
+static size_t min(size_t x, size_t y)
+{
+	return x < y ? x : y;
+}
+
+static const unsigned char PADDING_CHAR = '=';
+
+/**
+ * Pad the given buffer with len padding characters.
+ */
+static void pad(unsigned char *buf, int len)
+{
+	for (int i = 0; i < len; i++)
+		buf[i] = PADDING_CHAR;
+}
+
+/**
+ * This convert a 5 bits value into a base32 character.
+ * Only the 5 least significant bits are used.
+ */
+static unsigned char encode_char(unsigned char c)
+{
+	static unsigned char base32[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ234567";
+	return base32[c & 0x1F];  // 0001 1111
+}
+
+/**
+ * Decode given character into a 5 bits value. 
+ * Returns -1 iff the argument given was an invalid base32 character
+ * or a padding character.
+ */
+static int decode_char(unsigned char c)
+{
+	char retval = -1;
+
+	if (c >= 'A' && c <= 'Z')
+		retval = c - 'A';
+	if (c >= '2' && c <= '7')
+		retval = c - '2' + 26;
+
+	assert(retval == -1 || ((retval & 0x1F) == retval));
+
+	return  retval;
+}
+
+/**
+ * Given a block id between 0 and 7 inclusive, this will return the index of
+ * the octet in which this block starts. For example, given 3 it will return 1
+ * because block 3 starts in octet 1:
+ *
+ * +--------+--------+
+ * | ......<|.3 >....|
+ * +--------+--------+
+ *  octet 1 | octet 2
+ */
+static int get_octet(int block)
+{
+	assert(block >= 0 && block < 8);
+	return (block*5) / 8;
+}
+
+/**
+ * Given a block id between 0 and 7 inclusive, this will return how many bits
+ * we can drop at the end of the octet in which this block starts. 
+ * For example, given block 0 it will return 3 because there are 3 bits
+ * we don't care about at the end:
+ *
+ *  +--------+-
+ *  |< 0 >...|
+ *  +--------+-
+ *
+ * Given block 1, it will return -2 because there
+ * are actually two bits missing to have a complete block:
+ *
+ *  +--------+-
+ *  |.....< 1|..
+ *  +--------+-
+ **/
+static int get_offset(int block)
+{
+	assert(block >= 0 && block < 8);
+	return (8 - 5 - (5*block) % 8);
+}
+
+/**
+ * Like "b >> offset" but it will do the right thing with negative offset.
+ * We need this as bitwise shifting by a negative offset is undefined
+ * behavior.
+ */
+static unsigned char shift_right(unsigned char byte, char offset)
+{
+	if (offset > 0)
+		return byte >>  offset;
+	else
+		return byte << -offset;
+}
+
+static unsigned char shift_left(unsigned char byte, char offset)
+{
+	return shift_right(byte, - offset);
+}
+
+/**
+ * Encode a sequence. A sequence is no longer than 5 octets by definition.
+ * Thus passing a length greater than 5 to this function is an error. Encoding
+ * sequences shorter than 5 octets is supported and padding will be added to the
+ * output as per the specification.
+ */
+static void encode_sequence(const unsigned char *plain, int len, unsigned char *coded)
+{
+	assert(CHAR_BIT == 8);  // not sure this would work otherwise
+	assert(len >= 0 && len <= 5);
+
+	for (int block = 0; block < 8; block++) {
+		int octet = get_octet(block);  // figure out which octet this block starts in
+		int junk = get_offset(block);  // how many bits do we drop from this octet?
+
+		if (octet >= len) { // we hit the end of the buffer
+			pad(&coded[block], 8 - block);
+			return;
+		}
+
+		unsigned char c = shift_right(plain[octet], junk);  // first part
+
+		if (junk < 0  // is there a second part?
+		&&  octet < len - 1)  // is there still something to read?
+		{
+			c |= shift_right(plain[octet+1], 8 + junk);
+		}
+		coded[block] = encode_char(c);
+	}
+}
+
+void base32_encode(const unsigned char *plain, size_t len, unsigned char *coded)
+{
+	// All the hard work is done in encode_sequence(),
+	// here we just need to feed it the data sequence by sequence.
+	for (size_t i = 0, j = 0; i < len; i += 5, j += 8) {
+		encode_sequence(&plain[i], min(len - i, 5), &coded[j]);
+	}
+}
+
+static int decode_sequence(const unsigned char *coded, unsigned char *plain)
+{
+	assert(CHAR_BIT == 8);
+	assert(coded && plain);
+
+	plain[0] = 0;
+	for (int block = 0; block < 8; block++) {
+		int offset = get_offset(block);
+		int octet = get_octet(block);
+
+		int c = decode_char(coded[block]);
+		if (c < 0)  // invalid char, stop here
+			return octet;
+
+		plain[octet] |= shift_left(c, offset);
+		if (offset < 0) {  // does this block overflows to next octet?
+			assert(octet < 4);
+			plain[octet+1] = shift_left(c, 8 + offset);
+		}
+	}
+	return 5;
+}
+
+size_t base32_decode(const unsigned char *coded, unsigned char *plain)
+{
+	size_t written = 0;
+	for (size_t i = 0, j = 0; ; i += 8, j += 5) {
+		int n = decode_sequence(&coded[i], &plain[j]);
+		written += n;
+		if (n < 5)
+			return written;
+	}
+}

movement/lib/base32/base32.h

@@ -0,0 +1,66 @@
+/**
+ * base32 (de)coder implementation as specified by RFC4648.
+ *
+ * Copyright (c) 2010 Adrien Kunysz
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ **/
+
+#ifndef __BASE32_H_
+#define __BASE32_H_
+
+#include <stddef.h>   // size_t
+
+/**
+ * Returns the length of the output buffer required to encode len bytes of
+ * data into base32. This is a macro to allow users to define buffer size at
+ * compilation time.
+ */
+#define BASE32_LEN(len)  (((len)/5)*8 + ((len) % 5 ? 8 : 0))
+
+/**
+ * Returns the length of the output buffer required to decode a base32 string
+ * of len characters. Please note that len must be a multiple of 8 as per
+ * definition of a base32 string. This is a macro to allow users to define
+ * buffer size at compilation time.
+ */
+#define UNBASE32_LEN(len)  (((len)/8)*5)
+
+/**
+ * Encode the data pointed to by plain into base32 and store the
+ * result at the address pointed to by coded. The "coded" argument
+ * must point to a location that has enough available space
+ * to store the whole coded string. The resulting string will only
+ * contain characters from the [A-Z2-7=] set. The "len" arguments
+ * define how many bytes will be read from the "plain" buffer.
+ **/
+void base32_encode(const unsigned char *plain, size_t len, unsigned char *coded);
+
+/**
+ * Decode the null terminated string pointed to by coded and write
+ * the decoded data into the location pointed to by plain. The
+ * "plain" argument must point to a location that has enough available
+ * space to store the whole decoded string.
+ * Returns the length of the decoded string. This may be less than
+ * expected due to padding. If an invalid base32 character is found
+ * in the coded string, decoding will stop at that point.
+ **/
+size_t base32_decode(const unsigned char *coded, unsigned char *plain);
+
+#endif

movement/make/Makefile

@@ -21,6 +21,7 @@ INCLUDES += \
   -I../lib/sunriset/ \
   -I../lib/vsop87/ \
   -I../lib/astrolib/ \
+  -I../lib/base32/ \
 
 # If you add any other source files you wish to compile, add them after ../app.c
 # Note that you will need to add a backslash at the end of any line you wish to continue, i.e.
@@ -34,6 +35,7 @@ SRCS += \
   ../lib/sunriset/sunriset.c \
   ../lib/vsop87/vsop87a_milli.c \
   ../lib/astrolib/astrolib.c \
+  ../lib/base32/base32.c \
   ../../littlefs/lfs.c \
   ../../littlefs/lfs_util.c \
   ../movement.c \

movement/movement_config.h

@@ -29,6 +29,7 @@
 
 const watch_face_t watch_faces[] = {
     simple_clock_face,
+    totp_face,
     world_clock_face,
     sunrise_sunset_face,
     moon_phase_face,

movement/watch_faces/complication/totp_face.c

@@ -8,28 +8,57 @@
 #include "watch.h"
 #include "watch_utility.h"
 #include "TOTP.h"
+#include "base32.h"
+#include "filesystem.h"
 
 // test key: JBSWY3DPEHPK3PXP
 // Use https://cryptii.com/pipes/base32-to-hex to convert base32 to hex
 // Use https://totp.danhersam.com/ to generate test codes for verification
-static uint8_t hmacKey[] = {0x48, 0x65, 0x6c, 0x6c, 0x6f, 0x21, 0xde, 0xad, 0xbe, 0xef}; // Secret key
+static uint8_t last_filename_index = 0;
-
 
 static const uint32_t TIMESTEP = 30;
 
+static void read_totp_file(totp_state_t *totp_state) {
+    totp_state->valid = false;
+    char filename[12];
+    sprintf(filename, "totp%d.txt", totp_state->my_filename_index);
+    int32_t size = filesystem_get_file_size(filename);
+    if (size > 0) {
+        char *buf = malloc(size + 1);
+        filesystem_read_file(filename, buf, size);
+        char *site_name = strtok(buf, " \n");
+        char *hmac_string = strtok(NULL, " \n");
+        if (strlen(hmac_string) == 16) {
+            memcpy(totp_state->site_name, site_name, min(strlen(site_name), 2));
+            base32_decode(hmac_string, totp_state->hmac_key);
+            totp_state->valid = true;
+        }
+        free(buf);
+    }
+}
+
 void totp_face_setup(movement_settings_t *settings, uint8_t watch_face_index, void ** context_ptr) {
     (void) settings;
     (void) watch_face_index;
-    if (*context_ptr == NULL) *context_ptr = malloc(sizeof(totp_state_t));
+    if (*context_ptr == NULL) {
-    TOTP(hmacKey, sizeof(hmacKey), TIMESTEP);
+        *context_ptr = malloc(sizeof(totp_state_t));
+        (((totp_state_t *)(*context_ptr))->my_filename_index) = ++last_filename_index;
+        read_totp_file((totp_state_t *)(*context_ptr));
+    }
 }
 
 void totp_face_activate(movement_settings_t *settings, void *context) {
     (void) settings;
-    memset(context, 0, sizeof(totp_state_t));
     totp_state_t *totp_state = (totp_state_t *)context;
-    totp_state->timestamp = watch_utility_date_time_to_unix_time(watch_rtc_get_date_time(), movement_timezone_offsets[settings->bit.time_zone] * 60);
+    if (!totp_state->valid) {
-    totp_state->current_code = getCodeFromTimestamp(totp_state->timestamp);
+        read_totp_file(totp_state);
+    }
+    if (totp_state->valid) {
+        TOTP(totp_state->hmac_key, sizeof(totp_state->hmac_key), TIMESTEP);
+        totp_state->steps = 0;
+        totp_state->timestamp = watch_utility_date_time_to_unix_time(watch_rtc_get_date_time(), movement_timezone_offsets[settings->bit.time_zone] * 60);
+        totp_state->current_code = getCodeFromTimestamp(totp_state->timestamp);
+    }
 }
 
 bool totp_face_loop(movement_event_t event, movement_settings_t *settings, void *context) {
@@ -45,15 +74,25 @@ bool totp_face_loop(movement_event_t event, movement_settings_t *settings, void
             totp_state->timestamp++;
             // fall through
         case EVENT_ACTIVATE:
-            result = div(totp_state->timestamp, TIMESTEP);
+            if (totp_state->valid) {
-            if (result.quot != totp_state->steps) {
+                result = div(totp_state->timestamp, TIMESTEP);
-                totp_state->current_code = getCodeFromTimestamp(totp_state->timestamp);
+                if (result.quot != totp_state->steps) {
-                totp_state->steps = result.quot;
+                    totp_state->current_code = getCodeFromTimestamp(totp_state->timestamp);
+                    totp_state->steps = result.quot;
+                }
+                valid_for = TIMESTEP - result.rem;
+                sprintf(buf, "%s%2d%06lu", totp_state->site_name, valid_for, totp_state->current_code);
+                watch_display_string(buf, 0);
+            } else {
+                watch_display_string("2f  noCode", 0);
+                read_totp_file(totp_state);
+                if (totp_state->valid) {
+                    TOTP(totp_state->hmac_key, sizeof(totp_state->hmac_key), TIMESTEP);
+                    totp_state->steps = 0;
+                    totp_state->timestamp = watch_utility_date_time_to_unix_time(watch_rtc_get_date_time(), movement_timezone_offsets[settings->bit.time_zone] * 60);
+                    totp_state->current_code = getCodeFromTimestamp(totp_state->timestamp);
+                }
             }
-            valid_for = TIMESTEP - result.rem;
-            sprintf(buf, "2f%2d%06lu", valid_for, totp_state->current_code);
-
-            watch_display_string(buf, 0);
             break;
         case EVENT_MODE_BUTTON_UP:
             movement_move_to_next_face();

movement/watch_faces/complication/totp_face.h

@@ -4,10 +4,13 @@
 #include "movement.h"
 
 typedef struct {
+    char site_name[3];
+    uint8_t hmac_key[10];
     uint32_t timestamp;
     uint8_t steps;
     uint32_t current_code;
-
+    uint8_t my_filename_index;
+    bool valid;
 } totp_state_t;
 
 void totp_face_setup(movement_settings_t *settings, uint8_t watch_face_index, void ** context_ptr);