For those ignorant as me, https://redis.io/ .
Given the shame that shared network variables are, I would tend to say that any other solution, no matter how much of a contraption, might be attractive. I'm curious to read opinions too, as well as ideas for a LV API.
If you absolutely want to store information on a session level, you could use the CRYPTO_get_ex_new_index(CRYPTO_EX_INDEX_SSL/SSL_CTX, 0, "Name", NULL, NULL, NULL);
Then store the information on the ssl or ctx with SSL_set_ex_data() or SSL_CTX_set_ex_data().
Retrieve it with the according SSL_get_ex_data()/SSL_CTX_get_ex_data().