ALG_AES_IV_LEN
char cbuf[CMSG_SPACE(ALG_IV_LEN(ALG_AES_IV_LEN)) + CMSG_SPACE(ALG_OP_LEN)];
afalg_set_iv_sk(cmsg, iv, ALG_AES_IV_LEN);
if (ALG_AES_IV_LEN != EVP_CIPHER_CTX_get_iv_length(ctx)) {
char nxtiv[ALG_AES_IV_LEN] = { 0 };
memcpy(nxtiv, in + (inl - ALG_AES_IV_LEN), ALG_AES_IV_LEN);
memcpy(EVP_CIPHER_CTX_iv_noconst(ctx), out + (inl - ALG_AES_IV_LEN),
ALG_AES_IV_LEN);
memcpy(EVP_CIPHER_CTX_iv_noconst(ctx), nxtiv, ALG_AES_IV_LEN);