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RSL: implement RSL ENCR CMD, feed L3_INFO to LAPDm 

This is not full encrpytion support, the bts-model part still
needs to detect the ENCR CMD when de-queueing from LAPDm and enable
the de-ciphering, detect the arrival of the first encrypted frame,
etc, enable en-ciphering, ...
This commit is contained in:
Harald Welte 2011-07-07 11:48:00 +02:00
parent 39eadbbb17
commit 540410c123
1 changed files with 65 additions and 5 deletions
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70
src/common/rsl.c
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@ -513,6 +513,21 @@ static void copy_sacch_si_to_lchan(struct gsm_lchan *lchan)
}
static int encr_info2lchan(struct gsm_lchan *lchan,
const uint8_t *val, uint8_t len)
{
if (len < 2)
return -EINVAL;
lchan->encr.alg_id = *val++;
lchan->encr.key_len = len -1;
if (lchan->encr.key_len > sizeof(lchan->encr.key))
lchan->encr.key_len = sizeof(lchan->encr.key);
memcpy(lchan->encr.key, val, lchan->encr.key_len);
return 0;
}
/* 8.4.1 CHANnel ACTIVation is received */
static int rsl_rx_chan_activ(struct msgb *msg)
{
@ -543,11 +558,9 @@ static int rsl_rx_chan_activ(struct msgb *msg)
if (TLVP_PRESENT(&tp, RSL_IE_ENCR_INFO)) {
uint8_t len = TLVP_LEN(&tp, RSL_IE_ENCR_INFO);
const uint8_t *val = TLVP_VAL(&tp, RSL_IE_ENCR_INFO);
lchan->encr.alg_id = *val++;
lchan->encr.key_len = len -1;
if (lchan->encr.key_len > sizeof(lchan->encr.key))
lchan->encr.key_len = sizeof(lchan->encr.key);
memcpy(lchan->encr.key, val, lchan->encr.key_len);
if (encr_info2lchan(lchan, val, len) < 0)
return rsl_tx_error_report(msg->trx, RSL_ERR_IE_CONTENT);
}
/* 9.3.9 Handover Reference */
@ -632,6 +645,51 @@ static int rsl_rx_rf_chan_rel(struct msgb *msg)
return rc;
}
/* 8.4.6 ENCRYPTION COMMAND */
static int rsl_rx_encr_cmd(struct msgb *msg)
{
struct gsm_lchan *lchan = msg->lchan;
struct abis_rsl_dchan_hdr *dch = msgb_l2(msg);
struct tlv_parsed tp;
uint8_t link_id;
const uint8_t *l3_content;
if (rsl_tlv_parse(&tp, msgb_l3(msg), msgb_l3len(msg)) < 0)
return rsl_tx_error_report(msg->trx, RSL_ERR_IE_CONTENT);
if (!TLVP_PRESENT(&tp, RSL_IE_ENCR_INFO) ||
!TLVP_PRESENT(&tp, RSL_IE_L3_INFO) ||
!TLVP_PRESENT(&tp, RSL_IE_LINK_IDENT))
return rsl_tx_error_report(msg->trx, RSL_ERR_MAND_IE_ERROR);
/* 9.3.7 Encryption Information */
if (TLVP_PRESENT(&tp, RSL_IE_ENCR_INFO)) {
uint8_t len = TLVP_LEN(&tp, RSL_IE_ENCR_INFO);
const uint8_t *val = TLVP_VAL(&tp, RSL_IE_ENCR_INFO);
if (encr_info2lchan(lchan, val, len) < 0)
return rsl_tx_error_report(msg->trx, RSL_ERR_IE_CONTENT);
}
/* FIXME: check if the encryption algorithm sent by BSC is supported! */
/* 9.3.2 Link Identifier */
link_id = *TLVP_VAL(&tp, RSL_IE_LINK_IDENT);
/* pop the RSL dchan header */
l3_content = TLVP_VAL(&tp, RSL_IE_L3_INFO);
msgb_pull(msg, l3_content - msg->l2h);
/* push a fake RLL DATA REQ header */
rsl_rll_push_l3(msg, RSL_MT_DATA_REQ, dch->chan_nr, link_id, 1);
LOGP(DRSL, LOGL_INFO, "%s Fwd RSL ENCR CMD (Alg %u) to LAPDm\n",
gsm_lchan_name(lchan), lchan->encr.alg_id);
/* hand it into RSLms for transmission of L3_INFO to the MS */
return lapdm_rslms_recvmsg(msg, &lchan->lapdm_ch);
}
/* 8.4.20 SACCH INFO MODify */
static int rsl_rx_sacch_inf_mod(struct msgb *msg)
{
@ -1056,6 +1114,8 @@ static int rsl_rx_dchan(struct gsm_bts_trx *trx, struct msgb *msg)
ret = bts_model_rsl_deact_sacch(msg->lchan);
break;
case RSL_MT_ENCR_CMD:
ret = rsl_rx_encr_cmd(msg);
break;
case RSL_MT_MODE_MODIFY_REQ:
case RSL_MT_PHY_CONTEXT_REQ:
case RSL_MT_PREPROC_CONFIG: