TIPC_AES_GCM_TAG_SIZE
if (unlikely(skb->len <= ehsz + TIPC_AES_GCM_TAG_SIZE))
err = crypto_aead_setauthsize(tfm, TIPC_AES_GCM_TAG_SIZE);
tmp->authsize = TIPC_AES_GCM_TAG_SIZE;
#define EMSG_OVERHEAD (EHDR_SIZE + TIPC_AES_GCM_TAG_SIZE)
#define BUF_OVERHEAD (BUF_HEADROOM + TIPC_AES_GCM_TAG_SIZE)