bsd/netinet/tcp_sack.c

237 	struct sackhole *hole;
245 	hole = (struct sackhole *)zalloc_noblock(sack_hole_zone);
246 	if (hole == NULL)
249 	hole->start = start;
250 	hole->end = end;
251 	hole->rxmit = start;
256 	return hole;
263 tcp_sackhole_free(struct tcpcb *tp, struct sackhole *hole)
265 	zfree(sack_hole_zone, hole);
272  * Insert new SACK hole into scoreboard.
278 	struct sackhole *hole;
280 	/* Allocate a new SACK hole. */
281 	hole = tcp_sackhole_alloc(tp, start, end);
282 	if (hole == NULL)
285 	/* Insert the new SACK hole into scoreboard */
287 		TAILQ_INSERT_AFTER(&tp->snd_holes, after, hole, scblink);
289 		TAILQ_INSERT_TAIL(&tp->snd_holes, hole, scblink);
293 		tp->sackhint.nexthole = hole;
295 	return hole;
299  * Remove SACK hole from scoreboard.
302 tcp_sackhole_remove(struct tcpcb *tp, struct sackhole *hole)
305 	if (tp->sackhint.nexthole == hole)
306 		tp->sackhint.nexthole = TAILQ_NEXT(hole, scblink);
308 	/* Remove this SACK hole. */
309 	TAILQ_REMOVE(&tp->snd_holes, hole, scblink);
311 	/* Free this SACK hole. */
312 	tcp_sackhole_free(tp, hole);
398 		 * Append new SACK hole at the tail.
401 		 * way of hole splitting in the while-loop below.
410 			 * We failed to add a new hole based on the current
427 	/* We must have at least one SACK hole in scoreboard */
428 	cur = TAILQ_LAST(&tp->snd_holes, sackhole_head); /* Last SACK hole */
436 			 * SACKs data beyond the current hole.
444 			 * SACKs data before the current hole.
445 			 * Go to the previous hole.
452 			/* Data acks at least the beginning of hole */
454 				/* Acks entire hole, so delete hole */
460 				 * hole too, so continue onto the next hole.
464 				/* Move start of hole forward */
469 			/* Data acks at least the end of hole */
471 				/* Move end of hole backward */
476 				 * ACKs some data in middle of a hole; need to
477 				 * split current hole
497 		 * we're done with the sack block or the sack hole.
566 			if (SEQ_LT(p->rxmit, tp->snd_una)) {/* old SACK hole */
578  * Returns the next hole to retransmit and the number of retransmitted bytes
579  * from the scoreboard. We store both the next hole and the number of
584  * For the loop to traverse more than 1 link before finding the next hole to
590  * But that can't happen, (start == end) means that all the data in that hole
591  * has been sacked, in which case, the hole would have been removed from the
597 	struct sackhole *hole = NULL, *dbg_hole = NULL;
602 	hole = tp->sackhint.nexthole;
603 	if (hole == NULL || SEQ_LT(hole->rxmit, hole->end))
605 	while ((hole = TAILQ_NEXT(hole, scblink)) != NULL) {
606 		if (SEQ_LT(hole->rxmit, hole->end)) {
607 			tp->sackhint.nexthole = hole;
612 	if (dbg_hole != hole) {
613 		printf("%s: Computed sack hole not the same as cached value\n", __func__);
614 		hole = dbg_hole;
622 	return (hole);
641 	 * i) snd_nxt lies between end of one hole and beginning of another
642 	 * ii) snd_nxt lies between end of last hole and snd_fack