llc_queue: Refactor to handle codel_state per prio queue internally

A CoDel state per prio queue is needed, otherwise the sojourn time state
is not properly reset when a high prio packet is dequeued.

If we have a global codel state shared for all prio queues of an MS, then
basically high prio (GMM) packets will "never" be dropped because they are
handled/dequeued way quicker, so it's sojourn time will be below the
threshold most probably, stopping the "dropping" state for the rest of
lower prio packets.

The handling of different codel states is moved from MS object to the
llc_queue, also offloading already loaded dl_tbf.cpp in the process.
This will also allow in the future setting different CoDel parameters
for different priority queues if needed.

Tests need to be adapted since now the CoDel and PDU lifetime are
incorporated into the llc_queue_dequeue(). Also because dequeue now also
accesses related MS fields.

Related: OS#5508
Change-Id: I2bce2e82ab6389d8a70130a5c26a966a316b0fa4

1 files changed, 1 insertions, 78 deletions

diff --git a/src/tbf_dl.cpp b/src/tbf_dl.cpp
index 01b8f684..9c99cf6d 100644
--- a/src/tbf_dl.cpp
+++ b/src/tbf_dl.cpp
@@ -343,83 +343,6 @@ int dl_tbf_handle(struct gprs_rlcmac_bts *bts,
 	return rc;
 }
 
-struct msgb *gprs_rlcmac_dl_tbf::llc_dequeue(bssgp_bvc_ctx *bctx)
-{
-	struct msgb *msg;
-	struct timespec tv_now, tv_now2;
-	uint32_t octets = 0, frames = 0;
-	struct timespec hyst_delta = {0, 0};
-	const unsigned keep_small_thresh = 60;
-	const MetaInfo *info;
-
-	if (the_pcu->vty.llc_discard_csec)
-		csecs_to_timespec(the_pcu->vty.llc_discard_csec, &hyst_delta);
-
-	osmo_clock_gettime(CLOCK_MONOTONIC, &tv_now);
-	timespecadd(&tv_now, &hyst_delta, &tv_now2);
-
-	while ((msg = llc_queue_dequeue(llc_queue(), &info))) {
-		const struct timespec *tv_disc = &info->expire_time;
-		const struct timespec *tv_recv = &info->recv_time;
-
-		gprs_bssgp_update_queue_delay(tv_recv, &tv_now);
-
-		if (ms() && ms_codel_state(ms())) {
-			int bytes = llc_queue_octets(llc_queue());
-			if (gprs_codel_control(ms_codel_state(ms()),
-					tv_recv, &tv_now, bytes))
-				goto drop_frame;
-		}
-
-		/* Is the age below the low water mark? */
-		if (!llc_queue_is_frame_expired(&tv_now2, tv_disc))
-			break;
-
-		/* Is the age below the high water mark */
-		if (!llc_queue_is_frame_expired(&tv_now, tv_disc)) {
-			/* Has the previous message not been dropped? */
-			if (frames == 0)
-				break;
-
-			/* Hysteresis mode, try to discard LLC messages until
-			 * the low water mark has been reached */
-
-			/* Check whether to abort the hysteresis mode */
-
-			/* Is the frame small, perhaps only a TCP ACK? */
-			if (msg->len <= keep_small_thresh)
-				break;
-
-			/* Is it a GMM message? */
-			if (!llc_is_user_data_frame(msg->data, msg->len))
-				break;
-		}
-
-		bts_do_rate_ctr_inc(bts, CTR_LLC_FRAME_TIMEDOUT);
-drop_frame:
-		frames++;
-		octets += msg->len;
-		msgb_free(msg);
-		bts_do_rate_ctr_inc(bts, CTR_LLC_FRAME_DROPPED);
-		continue;
-	}
-
-	if (frames) {
-		LOGPTBFDL(this, LOGL_NOTICE, "Discarding LLC PDU "
-			"because lifetime limit reached, "
-			"count=%u new_queue_size=%zu\n",
-			  frames, llc_queue_size(llc_queue()));
-		if (frames > 0xff)
-			frames = 0xff;
-		if (octets > 0xffffff)
-			octets = 0xffffff;
-		if (bctx)
-			bssgp_tx_llc_discarded(bctx, tlli(), frames, octets);
-	}
-
-	return msg;
-}
-
 bool gprs_rlcmac_dl_tbf::restart_bsn_cycle()
 {
 	/* If V(S) == V(A) and finished state, we would have received
@@ -628,7 +551,7 @@ void gprs_rlcmac_dl_tbf::schedule_next_frame()
 		return;
 
 	/* dequeue next LLC frame, if any */
-	msg = llc_dequeue(bts->pcu->bssgp.bctx);
+	msg = llc_queue_dequeue(llc_queue());
 	if (!msg)
 		return;