X-Git-Url: http://git.meshlink.io/?a=blobdiff_plain;f=utcp.c;h=607af2d149ee9242646d3f1a97638ecb64e01078;hb=027abc36cfb0a8247625f5f6af65b7ce63065a33;hp=89a38b7d1c9546e94458531031b2ea419dad9cd6;hpb=1ba5f4c56c38b3c986dabb5d0feced74d81cd490;p=utcp

diff --git a/utcp.c b/utcp.c
index 89a38b7..607af2d 100644
--- a/utcp.c
+++ b/utcp.c
@@ -547,8 +547,11 @@ static void swap_ports(struct hdr *hdr) {
 }
 
 static void retransmit(struct utcp_connection *c) {
-	if(c->state == CLOSED || c->snd.nxt == c->snd.una)
+	if(c->state == CLOSED || c->snd.last == c->snd.una) {
+		debug("Retransmit() called but nothing to retransmit!\n");
+		stop_retransmit_timer(c);
 		return;
+	}
 
 	struct utcp *utcp = c->utcp;
 
@@ -630,7 +633,24 @@ cleanup:
 	free(pkt);
 }
 
-// Update receive buffer and SACK entries after consuming data.
+/* Update receive buffer and SACK entries after consuming data.
+ *
+ * Situation:
+ *
+ * |.....0000..1111111111.....22222......3333|
+ * |---------------^
+ *
+ * 0..3 represent the SACK entries. The ^ indicates up to which point we want
+ * to remove data from the receive buffer. The idea is to substract "len"
+ * from the offset of all the SACK entries, and then remove/cut down entries
+ * that are shifted to before the start of the receive buffer.
+ *
+ * There are three cases:
+ * - the SACK entry is ahead of ^, in that case just change the offset.
+ * - the SACK entry starts before and ends after ^, so we have to
+ *   change both its offset and size.
+ * - the SACK entry is completely before ^, in that case delete it.
+ */
 static void sack_consume(struct utcp_connection *c, size_t len) {
 	debug("sack_consume %zu\n", len);
 	if(len > c->rcvbuf.used)
@@ -643,13 +663,13 @@ static void sack_consume(struct utcp_connection *c, size_t len) {
 			c->sacks[i].offset -= len;
 			i++;
 		} else if(len < c->sacks[i].offset + c->sacks[i].len) {
-			c->sacks[i].offset = 0;
 			c->sacks[i].len -= len - c->sacks[i].offset;
+			c->sacks[i].offset = 0;
 			i++;
 		} else {
 			if(i < NSACKS - 1) {
 				memmove(&c->sacks[i], &c->sacks[i + 1], (NSACKS - 1 - i) * sizeof c->sacks[i]);
-				c->sacks[i + 1].len = 0;
+				c->sacks[NSACKS - 1].len = 0;
 			} else {
 				c->sacks[i].len = 0;
 				break;