paging: pass struct osmo_mobile_identity, not encoded IE bytes
In get_paging_mi(), before this, an encoded buffer of Mobile Identity bytes is
returned. Code paths following this repeatedly decode the Mobile Identity
bytes, e.g. for logging. Also, in get_paging_mi(), since the TMSI is read in
from a different encoding than a typical Mobile Identity IE, the TMSI was
manually encoded into a typical Mobile Identity IE. This is essentially a code
dup of osmo_mobile_identity_encode(). Stop this madness.
Instead, in get_paging_mi(), return a decoded struct osmo_mobile_identity. Code
paths after this use the struct osmo_mobile_identity directly without repeated
decoding.
At the point of finally needing an encoded Mobile Identity IE (in
Encoding::write_paging_request()), do a proper osmo_mobile_identity_encode().
Since this may return errors, add an rc check for the caller of
write_paging_request(), gprs_rlcmac_paging_request().
A side effect is stricter validation of the Mobile Identity passing through the
Paging code path. Before, invalid MI might have passed through unnoticed.
Change-Id: Iad845acb0096b75dc453105c9c16b2252879b4ca
diff --git a/src/gprs_bssgp_pcu.cpp b/src/gprs_bssgp_pcu.cpp
index a46852a..14d1a9d 100644
--- a/src/gprs_bssgp_pcu.cpp
+++ b/src/gprs_bssgp_pcu.cpp
@@ -171,11 +171,8 @@
}
/* Returns 0 on success, suggested BSSGP cause otherwise */
-static unsigned int get_paging_mi(const uint8_t **mi, uint8_t *mi_len,
- const struct tlv_parsed *tp)
+static unsigned int get_paging_mi(struct osmo_mobile_identity *mi, const struct tlv_parsed *tp)
{
- static uint8_t tmsi_buf[GSM48_TMSI_LEN];
-
/* Use TMSI (if present) or IMSI */
if (TLVP_PRESENT(tp, BSSGP_IE_TMSI)) {
/* Be safe against an evil SGSN - check the length */
@@ -185,14 +182,17 @@
}
/* NOTE: TMSI (unlike IMSI) IE comes without MI type header */
- memcpy(tmsi_buf + 1, TLVP_VAL(tp, BSSGP_IE_TMSI), GSM23003_TMSI_NUM_BYTES);
- tmsi_buf[0] = 0xf0 | GSM_MI_TYPE_TMSI;
-
- *mi_len = GSM48_TMSI_LEN;
- *mi = tmsi_buf;
+ *mi = (struct osmo_mobile_identity){
+ .type = GSM_MI_TYPE_TMSI,
+ };
+ mi->tmsi = osmo_load32be(TLVP_VAL(tp, BSSGP_IE_TMSI));
} else if (TLVP_PRESENT(tp, BSSGP_IE_IMSI)) {
- *mi_len = TLVP_LEN(tp, BSSGP_IE_IMSI);
- *mi = TLVP_VAL(tp, BSSGP_IE_IMSI);
+ int rc = osmo_mobile_identity_decode(mi, TLVP_VAL(tp, BSSGP_IE_IMSI), TLVP_LEN(tp, BSSGP_IE_IMSI),
+ true);
+ if (rc < 0 || mi->type != GSM_MI_TYPE_IMSI) {
+ LOGP(DBSSGP, LOGL_ERROR, "Invalid IMSI Mobile Identity\n");
+ return BSSGP_CAUSE_COND_IE_ERR;
+ }
} else {
LOGP(DBSSGP, LOGL_ERROR, "Neither TMSI IE nor IMSI IE is present\n");
return BSSGP_CAUSE_MISSING_COND_IE;
@@ -203,23 +203,21 @@
static int gprs_bssgp_pcu_rx_paging_cs(struct msgb *msg, struct tlv_parsed *tp)
{
- const uint8_t *mi;
- uint8_t mi_len;
+ struct osmo_mobile_identity mi;
int rc;
uint8_t *chan_needed = (uint8_t *)TLVP_VAL(tp, BSSGP_IE_CHAN_NEEDED);
- if ((rc = get_paging_mi(&mi, &mi_len, tp)) > 0)
+ if ((rc = get_paging_mi(&mi, tp)) > 0)
return bssgp_tx_status((enum gprs_bssgp_cause) rc, NULL, msg);
- return BTS::main_bts()->add_paging(chan_needed ? *chan_needed : 0, mi, mi_len);
+ return BTS::main_bts()->add_paging(chan_needed ? *chan_needed : 0, &mi);
}
static int gprs_bssgp_pcu_rx_paging_ps(struct msgb *msg, struct tlv_parsed *tp)
{
struct osmo_mobile_identity mi_imsi;
+ struct osmo_mobile_identity paging_mi;
uint16_t pgroup;
- const uint8_t *mi;
- uint8_t mi_len;
int rc;
if (!TLVP_PRESENT(tp, BSSGP_IE_IMSI)) {
@@ -238,10 +236,10 @@
return bssgp_tx_status(BSSGP_CAUSE_INV_MAND_INF, NULL, msg);
}
- if ((rc = get_paging_mi(&mi, &mi_len, tp)) > 0)
+ if ((rc = get_paging_mi(&paging_mi, tp)) > 0)
return bssgp_tx_status((enum gprs_bssgp_cause) rc, NULL, msg);
- return gprs_rlcmac_paging_request(mi, mi_len, pgroup);
+ return gprs_rlcmac_paging_request(&paging_mi, pgroup);
}
/* Receive a BSSGP PDU from a BSS on a PTP BVCI */