Add check of lifetime of LLC frame

If lifetime expires of queued LLC frames, they are discarded. The number
of discarded frames and the sum of their octets are reported to SGSN
via LLC-DISCARDED message.

The lifetime can be overridden via VTY. The value can be centi-seconds
or "infinite".

1 files changed, 45 insertions, 2 deletions

diff --git a/src/gprs_rlcmac_data.cpp b/src/gprs_rlcmac_data.cpp
index 10bc0177..2f67bd0a 100644
--- a/src/gprs_rlcmac_data.cpp
+++ b/src/gprs_rlcmac_data.cpp
@@ -22,6 +22,11 @@
 #include <gprs_rlcmac.h>
 #include <pcu_l1_if.h>
 
+extern "C" {
+int bssgp_tx_llc_discarded(struct bssgp_bvc_ctx *bctx, uint32_t tlli,
+                           uint8_t num_frames, uint32_t num_octets);
+}
+
 /* After receiving these frames, we send ack/nack. */
 #define SEND_ACK_AFTER_FRAMES 20
 
@@ -868,6 +873,44 @@ int gprs_rlcmac_rcv_rach(uint8_t ra, uint32_t Fn, int16_t qta)
  * DL data block flow
  */
 
+static struct msgb *llc_dequeue(struct gprs_rlcmac_tbf *tbf)
+{
+	struct msgb *msg;
+	struct timeval *tv, tv_now;
+	uint32_t octets = 0, frames = 0;
+
+	gettimeofday(&tv_now, NULL);
+
+	while ((msg = msgb_dequeue(&tbf->llc_queue))) {
+		tv = (struct timeval *)msg->data;
+		msgb_pull(msg, sizeof(*tv));
+		if (tv->tv_sec /* not infinite */
+		 && (tv_now.tv_sec > tv->tv_sec /* and secs expired */
+		  || (tv_now.tv_sec == tv->tv_sec /* .. or if secs equal .. */
+		   && tv_now.tv_usec > tv->tv_usec))) { /* .. usecs expired */
+			LOGP(DRLCMACDL, LOGL_NOTICE, "Discarding LLC PDU of "
+				"DL TBF=%d, because lifetime limit reached\n",
+				tbf->tfi);
+			frames++;
+			octets += msg->len;
+			msgb_free(msg);
+			continue;
+		}
+		break;
+	}
+
+	if (frames) {
+		if (frames > 0xff)
+			frames = 0xff;
+		if (octets > 0xffffff)
+			octets = 0xffffff;
+		bssgp_tx_llc_discarded(bctx, tbf->tlli, frames, octets);
+	}
+
+	return msg;
+}
+
+
 /* send DL data block
  *
  * The messages are fragmented and forwarded as data blocks.
@@ -1083,7 +1126,7 @@ do_resend:
 		/* reset LLC frame */
 		tbf->llc_index = tbf->llc_length = 0;
 		/* dequeue next LLC frame, if any */
-		msg = msgb_dequeue(&tbf->llc_queue);
+		msg = llc_dequeue(tbf);
 		if (msg) {
 			LOGP(DRLCMACDL, LOGL_INFO, "- Dequeue next LLC for "
 				"TBF=%d (len=%d)\n", tbf->tfi, msg->len);
@@ -1281,7 +1324,7 @@ int gprs_rlcmac_downlink_ack(struct gprs_rlcmac_tbf *tbf, uint8_t final,
 		LOGP(DRLCMACDL, LOGL_DEBUG, "- Final ACK received.\n");
 
 	/* check for LLC PDU in the LLC Queue */
-	msg = msgb_dequeue(&tbf->llc_queue);
+	msg = llc_dequeue(tbf);
 	if (!msg) {
 		struct gprs_rlcmac_bts *bts = gprs_rlcmac_bts;