ms: Support new and old TLLIs
According to the specification (GSM 04.08/24.008, 4.7.1.5) after a
new P-TMSI has been assigned, the old P-TMSI must be kept basically
until it has been used by both sides. Since the TLLI will be derived
from the P-TMSI, the old TLLI must also be kept until the new TLLI
has been used by both MS and SGSN.
This commit modifies the TLLI handling of GprsMs accordingly.
set_tlli() is only used with TLLIs derived from MS messages,
confirm_tlli() is used with TLLIs derived from messages received from
the SGSN. tlli() returns the value set by the MS. check_tlli()
matches each of the TLLI used by either MS or SGSN as well as the old
TLLI until it has been confirmed.
Sponsored-by: On-Waves ehf
diff --git a/src/gprs_bssgp_pcu.cpp b/src/gprs_bssgp_pcu.cpp
index db271a5..1c35667 100644
--- a/src/gprs_bssgp_pcu.cpp
+++ b/src/gprs_bssgp_pcu.cpp
@@ -118,6 +118,7 @@
struct bssgp_ud_hdr *budh;
uint32_t tlli;
+ uint32_t tlli_old = 0;
uint8_t *data;
uint16_t len;
char imsi[16] = "000";
@@ -163,9 +164,22 @@
LOGP(DBSSGP, LOGL_NOTICE, "BSSGP missing mandatory "
"PDU_LIFETIME IE\n");
+ /* get optional TLLI old */
+ if (TLVP_PRESENT(tp, BSSGP_IE_TLLI))
+ {
+ uint8_t tlli_len = TLVP_LEN(tp, BSSGP_IE_PDU_LIFETIME);
+ uint16_t *e_tlli_old = (uint16_t *) TLVP_VAL(tp, BSSGP_IE_TLLI);
+ if (tlli_len == 2)
+ tlli_old = ntohs(*e_tlli_old);
+ else
+ LOGP(DBSSGP, LOGL_NOTICE, "BSSGP invalid length of "
+ "TLLI (old) IE\n");
+ }
+
LOGP(DBSSGP, LOGL_INFO, "LLC [SGSN -> PCU] = TLLI: 0x%08x IMSI: %s len: %d\n", tlli, imsi, len);
- return gprs_rlcmac_dl_tbf::handle(the_pcu.bts, tlli, imsi, ms_class, delay_csec, data, len);
+ return gprs_rlcmac_dl_tbf::handle(the_pcu.bts, tlli, tlli_old, imsi,
+ ms_class, delay_csec, data, len);
}
int gprs_bssgp_pcu_rx_paging_ps(struct msgb *msg, struct tlv_parsed *tp)