Change in libosmocore[master]: gprs_ns2_vc_fsm: check NSVCI match the NSE

[lynxis lazus]

lynxis lazus has uploaded this change for review. ( https://gerrit.osmocom.org/c/libosmocore/+/22425 )


Change subject: gprs_ns2_vc_fsm: check NSVCI match the NSE
......................................................................

gprs_ns2_vc_fsm: check NSVCI match the NSE

The NSVCI must match the PDUs. The only exception is a RESET with
dialect ipaccess. However those will be handled later.

Change-Id: I0ebdd4f4135b03a7d44a93aff3846c8ec19f333b
---
M src/gb/gprs_ns2_vc_fsm.c
1 file changed, 14 insertions(+), 2 deletions(-)



  git pull ssh://gerrit.osmocom.org:29418/libosmocore refs/changes/25/22425/1

diff --git a/src/gb/gprs_ns2_vc_fsm.c b/src/gb/gprs_ns2_vc_fsm.c
index 3ec6909..d4f4320 100644
--- a/src/gb/gprs_ns2_vc_fsm.c
+++ b/src/gb/gprs_ns2_vc_fsm.c
@@ -750,11 +750,10 @@
 	struct osmo_fsm_inst *fi = nsvc->fi;
 	int rc = 0;
 	uint8_t cause;
-	uint16_t nsei;
+	uint16_t nsei, nsvci;
 
 	/* TODO: 7.2: on UNBLOCK/BLOCK: check if NS-VCI is correct,
 	 *  if not answer STATUS with "NS-VC unknown" */
-	/* TODO: handle RESET with different VCI */
 	/* TODO: handle BLOCK/UNBLOCK/ALIVE with different VCI */
 
 	if (gprs_ns2_validate(nsvc, nsh->pdu_type, msg, tp, &cause)) {
@@ -777,6 +776,19 @@
 		}
 	}
 
+	if (nsvc->nsvci_is_valid && TLVP_PRESENT(tp,  NS_IE_VCI)) {
+		nsvci = tlvp_val16be(tp, NS_IE_VCI);
+		if (nsvci != nsvc->nsvci) {
+			/* 48.016 § 7.3.1 send RESET_ACK to wrong NSVCI + ignore */
+			if (nsh->pdu_type == NS_PDUT_RESET)
+				ns2_tx_reset_ack(nsvc);
+
+			LOGNSVC(nsvc, LOGL_ERROR, "Rx %s with wrong NSVCI=%05u. Ignoring PDU.\n",
+				get_value_string(gprs_ns_pdu_strings, nsh->pdu_type), nsvci);
+			goto out;
+		}
+	}
+
 	switch (nsh->pdu_type) {
 	case NS_PDUT_RESET:
 		osmo_fsm_inst_dispatch(fi, GPRS_NS2_EV_RX_RESET, tp);

-- 
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Gerrit-Project: libosmocore
Gerrit-Branch: master
Gerrit-Change-Id: I0ebdd4f4135b03a7d44a93aff3846c8ec19f333b
Gerrit-Change-Number: 22425
Gerrit-PatchSet: 1
Gerrit-Owner: lynxis lazus <lynxis at fe80.eu>
Gerrit-MessageType: newchange
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