• rslms_recvmsg() frees message if discriminator is not known,

otherwhise it forward it to rslms_rx_rll().

• rslms_rx_rll() forwards messages to rslms_rx_rll_*_req(), but does

not free it when RLL message type is unknown.

it seems that the message is freed by the receiving layer (or function), but i cannot understand why layer2_read() in main.c does it after calling l1ctl_recv.