RLC TM can't be segmented so it may happen that a PDU
cannot be sent because the grant is too small. That is not
an error and should only be logged in info.
this fixes a potential access of invalid PHY or MAC metrics by checking
the user entry actually exists.
the RFCI has shown this error:
------DL--------------------------------UL------------------------------------
rnti cqi ri mcs brate ok nok (%) snr phr mcs brate ok nok (%) bsr
ASAN:DEADLYSIGNAL
=================================================================
m==31838==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000000 (pc 0x555d482b6893 bp 0x7f6ac32d1160 sp 0x7f6ac32d0bc0 T21)
==31838==The signal is caused by a READ memory access.
==31838==Hint: address points to the zero page.
#0 0x555d482b6892 in srsenb::metrics_stdout::set_metrics(srsenb::enb_metrics_t const&, unsigned int) /mnt/data/jenkins/workspace/srslte_dev_ogt_zmq_nightly/srsLTE/srsenb/src/metrics_stdout.cc:101
#1 0x555d482865f1 in srslte::metrics_hub<srsenb::enb_metrics_t>::run_period() /mnt/data/jenkins/workspace/srslte_dev_ogt_zmq_nightly/srsLTE/lib/include/srslte/common/metrics_hub.h:88
#2 0x555d482865f1 in srslte::periodic_thread::run_thread() /mnt/data/jenkins/workspace/srslte_dev_ogt_zmq_nightly/srsLTE/lib/include/srslte/common/threads.h:143
#3 0x555d4826813d in srslte:🧵:thread_function_entry(void*) /mnt/data/jenkins/workspace/srslte_dev_ogt_zmq_nightly/srsLTE/lib/include/srslte/common/threads.h:102
#4 0x7f6b0dc546da in start_thread (/lib/x86_64-linux-gnu/libpthread.so.0+0x76da)
#5 0x7f6b0bf0171e in __clone (/lib/x86_64-linux-gnu/libc.so.6+0x12171e)
we've logged in warning mode bc we don't support IPv6 but its
causing unwanted noise in the epc log file.
it's quite normal that the Linux network stack sends IPv6 router
solicitation packets, etc. So we just ignore them and that's it.
when retrieving the RLC metrics, the number of TTIs since the last
call are passed. This allows to calculate the actual rate
based on the LTE timing rather than only the system timing.
we've only incremented the retx when retransmitting a full PDU,
but not when only retransmitting segments.
This might lead to many more retx than allowed.