diff options
Diffstat (limited to 'src/common/l1sap.c')
| -rw-r--r-- | src/common/l1sap.c | 45 |
1 files changed, 35 insertions, 10 deletions
diff --git a/src/common/l1sap.c b/src/common/l1sap.c index c2120b04..d165639a 100644 --- a/src/common/l1sap.c +++ b/src/common/l1sap.c @@ -481,6 +481,39 @@ static void radio_link_timeout(struct gsm_lchan *lchan, int bad_frame) } } +static inline int check_for_first_ciphrd(struct gsm_lchan *lchan, + uint8_t *data, int len) +{ + uint8_t n_s; + + /* if this is the first valid message after enabling Rx + * decryption, we have to enable Tx encryption */ + if (lchan->ciph_state != LCHAN_CIPH_RX_CONF) + return 0; + + /* HACK: check if it's an I frame, in order to + * ignore some still buffered/queued UI frames received + * before decryption was enabled */ + if (data[0] != 0x01) + return 0; + + if ((data[1] & 0x01) != 0) + return 0; + + n_s = data[1] >> 5; + if (lchan->ciph_ns != n_s) + return 0; + + return 1; +} + +/* public helper for the test */ +int bts_check_for_first_ciphrd(struct gsm_lchan *lchan, + uint8_t *data, int len) +{ + return check_for_first_ciphrd(lchan, data, len); +} + /* DATA received from bts model */ static int l1sap_ph_data_ind(struct gsm_bts_trx *trx, struct osmo_phsap_prim *l1sap, struct ph_data_param *data_ind) @@ -557,16 +590,8 @@ static int l1sap_ph_data_ind(struct gsm_bts_trx *trx, } else le = &lchan->lapdm_ch.lapdm_dcch; - /* if this is the first valid message after enabling Rx - * decryption, we have to enable Tx encryption */ - if (lchan->ciph_state == LCHAN_CIPH_RX_CONF) { - /* HACK: check if it's an I frame, in order to - * ignore some still buffered/queued UI frames received - * before decryption was enabled */ - if (data[0] == 0x01 && (data[1] & 0x01) == 0) { - l1sap_tx_ciph_req(trx, chan_nr, 1, 0); - } - } + if (check_for_first_ciphrd(lchan, data, len)) + l1sap_tx_ciph_req(lchan->ts->trx, chan_nr, 1, 0); /* SDCCH, SACCH and FACCH all go to LAPDm */ msgb_pull(msg, (msg->l2h - msg->data)); |