diff options
| -rw-r--r-- | openbsc/src/bssap.c | 46 |
1 files changed, 43 insertions, 3 deletions
diff --git a/openbsc/src/bssap.c b/openbsc/src/bssap.c index ffc549852..26ab998fa 100644 --- a/openbsc/src/bssap.c +++ b/openbsc/src/bssap.c @@ -56,6 +56,8 @@ static const struct tlv_definition bss_att_tlvdef = { [GSM0808_IE_CONFIG_EVO_INDI] = { TLV_TYPE_TV }, [GSM0808_IE_LSA_ACCESS_CTRL_SUPPR] = { TLV_TYPE_TV }, [GSM0808_IE_SERVICE_HANDOVER] = { TLV_TYPE_TV}, + [GSM0808_IE_ENCRYPTION_INFORMATION] = { TLV_TYPE_TLV }, + [GSM0808_IE_CIPHER_RESPONSE_MODE] = { TLV_TYPE_TV }, }, }; @@ -191,8 +193,13 @@ static int bssmap_handle_clear_command(struct sccp_connection *conn, static int bssmap_handle_cipher_mode(struct sccp_connection *conn, struct msgb *msg, unsigned int payload_length) { + u_int16_t len; + struct gsm_network *network = NULL; + const u_int8_t *data; + struct tlv_parsed tp; struct msgb *resp; int reject_cause = -1; + int include_imeisv = 1; /* HACK: Sending A5/0 to the MS */ if (!msg->lchan || !msg->lchan->msc_data) { @@ -207,10 +214,43 @@ static int bssmap_handle_cipher_mode(struct sccp_connection *conn, msg->lchan->msc_data->ciphering_handled = 1; - /* FIXME: parse the message. TLVP */ -#warning "Need to handle cipher mode properly" + tlv_parse(&tp, &bss_att_tlvdef, msg->l4h + 1, payload_length - 1, 0, 0); + if (!TLVP_PRESENT(&tp, GSM0808_IE_ENCRYPTION_INFORMATION)) { + DEBUGP(DMSC, "IE Encryption Information missing.\n"); + goto reject; + } + + /* + * check if our global setting is allowed + * - Currently we check for A5/0 and A5/1 + * - Copy the key if that is necessary + * - Otherwise reject + */ + len = TLVP_LEN(&tp, GSM0808_IE_ENCRYPTION_INFORMATION); + if (len < 1) { + DEBUGP(DMSC, "IE Encryption Information is too short.\n"); + goto reject; + } + + network = msg->lchan->ts->trx->bts->network; + data = TLVP_VAL(&tp, GSM0808_IE_ENCRYPTION_INFORMATION); + + if (network->a5_encryption == 0 && (data[0] & 0x1) == 0x1) { + msg->lchan->encr.alg_id = RSL_ENC_ALG_A5(0); + } else if (network->a5_encryption != 0 && (data[0] & 0x2) == 0x2) { + msg->lchan->encr.alg_id = RSL_ENC_ALG_A5(1); + msg->lchan->encr.key_len = len - 1; + memcpy(msg->lchan->encr.key, &data[1], len - 1); + } else { + DEBUGP(DMSC, "Can not select encryption...\n"); + goto reject; + } + + if (TLVP_PRESENT(&tp, GSM0808_IE_CIPHER_RESPONSE_MODE)) { + include_imeisv = TLVP_VAL(&tp, GSM0808_IE_CIPHER_RESPONSE_MODE)[0] & 0x1; + } - return gsm48_send_rr_ciph_mode(msg->lchan, 1); + return gsm48_send_rr_ciph_mode(msg->lchan, include_imeisv); reject: resp = bssmap_create_cipher_reject(reject_cause); |