when adding a new subheader to a MAC PDU we should only add the subheader
if at least 2 bytes are left in the PDU. Even a 1 Byte MAC Control Element requires
another byte to pack the subheader.
This fixes#1424 in which a 3 B MAC opportunity is provided in the UL. After
adding the Short BSR, we tried to add another MAC subheader. Adding the subheader
succeeded even though no space is left to add a single byte. With this patch,
adding the subheader fails and the generates MAC PDU is correct.
with ZMQ RF, we've seen the radio returning -1 and traced
the issue down to the ringbuffer.
in fact, pthread_cond_timedwait() returned 22 (EINVAL) indicating
a wrong timeout value. The issue was likely an overflow
in the timespec parameter. This patch checks for the return
value of pthread_cond_timedwait() and also calculates the
nanosecond wrap around for the timespec
amarisoft flags an RF error and exits after not receiving samples
for the radio. Running with ZMQ in the RFCI, the UE sometimes needs more
time to start up due to slow processing and no fftw wisdom file and
then Amarisoft eNB times out. This gives the whole process a little
bit more time. Should we still find it too short we may increase
it further.
This lock was removed in 1cbf7eac because it was considered unneeded.
However, as can be seen in issue #1503, we need to protect the access
to rx_window, for example.
Issue #1503 shows a stack trace where a PHY worker generates a status PDU.
While holding the mutex to access rx_window, the stack thread on the
other hand, happily accesses the rx_window member without acquiring
the lock. This commit protects all handle_*() functions in write_pdu().
This reverts commit 1cbf7eac04.
instead of logging PDU received from below, and SDU that is forwarded
to above, only log the PDU in rx in info mode.
The next layer will do the same and log the PDU received (which is the SDU coming from here)
so there is now loss of information in the logs.
Here is the test output with the fix disabled:
13:47:42.679774 [RLC_UM_1] [D] MAC opportunity - 14 bytes
13:47:42.679784 [RLC_UM_1] [D] pdu_space=14, head_len=2
13:47:42.679790 [RLC_UM_1] [D] adding new SDU segment - 10 bytes of 10 remaining
13:47:42.679834 [RLC_UM_1] [D] Complete SDU scheduled for tx. Stack latency: 0 us
13:47:42.679909 [RLC_UM_1] [D] pdu_space=4, head_len=2
13:47:42.679922 [RLC_UM_1] [D] adding new SDU segment - 0 bytes of 10 remaining
13:47:42.679928 [RLC_UM_1] [I] Tx PDU SN=0 (14 B)
13:47:42.679974 [RLC_UM_1] [D] vt_us = 1
The test checks the correct packing and of the two PDUs at the end.
during the PDU packing it could happen that a new SDU segment
was added but the resulting larger header was so big that not even
a single byte of the new PDU could be added. because this
corner case wasn't handled correctly an invalid PDU was transmitted.
the solution is to revert the addition of the new SDU.