- if (num_interfaces == 2)
- printf("%s -> %s (%s) = %s (%s)\n",
- S(mi->ts_sent), S(mi->ts_rx_final_kern), S(mi->ts_rx_final),
- DIFF(mi->ts_sent, mi->ts_rx_final_kern),
- DIFF(mi->ts_sent, mi->ts_rx_final));
- else
- printf("%s -> %s (%s) -> %s (%s) = %s (%s), %s (%s)\n",
- S(mi->ts_sent),
- S(mi->ts_rx_onwire_kern), S(mi->ts_rx_onwire),
- S(mi->ts_rx_final_kern), S(mi->ts_rx_final),
- DIFF(mi->ts_sent, mi->ts_rx_onwire_kern),
- DIFF(mi->ts_sent, mi->ts_rx_onwire),
- DIFF(mi->ts_rx_onwire_kern, mi->ts_rx_final_kern),
- DIFF(mi->ts_rx_onwire, mi->ts_rx_final));
-#undef S
-#undef DIFF
- talloc_free (local);
+unsigned calc_stuff_bits(struct can_frame *frame) {
+ uint32_t bitmap[4];
+ unsigned start = 0, end;
+ uint32_t mask, ones = 0, basemask = 0xf8000000;
+ unsigned stuffed = 0;
+ memset(bitmap, 0, sizeof(bitmap));
+ uint32_t crc;
+
+/* char received[64]; */
+/* sprint_canframe(received, frame, true); */
+/* printf("Frame: %s\n", received); */
+
+ if (frame->can_id & CAN_EFF_FLAG) {
+ // bit 31 0
+ // [0] |...........................sBBBB| s = SOF, B = Base ID (11 bits)
+ // [1] |BBBBBBBSIEEEEEEEEEEEEEEEEEER10DLC4| S = SRR, I = IDE, E = Extended ID (18 bits), DLC4 = DLC
+ // [2] |00000000111111112222222233333333| Data bytes, MSB first
+ // [3] |44444444555555556666666677777777|
+ bitmap[0] =
+ ((frame->can_id & CAN_EFF_MASK) >> 25);
+ bitmap[1] =
+ ((frame->can_id & CAN_EFF_MASK) >> 18) << 25 |
+ 3 << 23 |
+ ((frame->can_id & CAN_EFF_MASK) & 0x3ffff) << 7 |
+ (!!(frame->can_id & CAN_RTR_FLAG)) << 6 |
+ 0 << 4 |
+ frame->can_dlc & 0xf;
+ memcpy(&bitmap[2], &frame->data, frame->can_dlc);
+ start = 27;
+ end = 64 + 8*frame->can_dlc;
+ } else {
+ // bit 31 0
+ // [0] |.............sIIIIIIIIIIIRE0DLC4| s = SOF, I = ID (11 bits), R = RTR, E = IDE, DLC4 = DLC
+ // [1] |00000000111111112222222233333333| Data bytes, MSB first
+ // [2] |44444444555555556666666677777777|
+ bitmap[0] =
+ (frame->can_id << 7) |
+ (!!(frame->can_id & CAN_RTR_FLAG)) << 6 |
+ 0 << 4 |
+ frame->can_dlc & 0xf;
+ memcpy(&bitmap[1], &frame->data, frame->can_dlc);
+ start = 13;
+ end = 32 + 8*frame->can_dlc;
+ }
+ crc = calc_bitmap_crc(bitmap, start, end);
+ uint32_t crc_be = htons(crc << 17);
+ memcpy((char*)bitmap + end/8, &crc_be, 2); /* end is guaranteed to be divisible by 8 */
+ end += 15;
+
+ while (start < end) {
+ mask = basemask >> (start & 0x1f);
+ while (1) {
+ ones = ones ? mask : 0;
+ uint32_t chunk = (bitmap[start >> 5] & mask) ^ ones;
+ //printf("start=%d bitmap=0x%08x mask=0x%08x ones=0x%08x chunk=0x%08x\n", start, bitmap[start >> 5], mask, ones, chunk);
+ if (chunk) {
+ unsigned change = __builtin_clz(chunk);
+ start = start & ~0x1f | change;
+ basemask = 0xf8000000;
+ } else {
+ unsigned oldstart = start;
+ start += __builtin_popcount(mask);
+ mask = (oldstart & 0x1f) ? basemask << (-oldstart & 0x1f) : 0;
+ //printf("oldstart=%d shl=%d mask=0x%08x\n", oldstart, -oldstart & 0x1f, mask);
+ if (mask && start < end)
+ continue;
+ if (start <= end && !mask) {
+ stuffed++;
+ basemask = 0xf0000000;
+ //printf("stuffed %d\n", !ones);
+ }
+ }
+ break;
+ }
+ ones = !ones;
+ }
+ //printf ("STUFFED %d BITS\n", stuffed);
+ return stuffed;