X-Git-Url: http://git.meshlink.io/?a=blobdiff_plain;f=utcp.c;h=95a82c428710ca91f5f2752045eea036bee40c79;hb=05ee8ad65c1c7f1318e1185ddf299a2cce6c6474;hp=7c577018888b0fd99b7cac6f9d66e29b9a0fd91c;hpb=64ef5642d83fc13829262ec6c1bddb6a20d9aa7a;p=utcp

diff --git a/utcp.c b/utcp.c
index 7c57701..95a82c4 100644
--- a/utcp.c
+++ b/utcp.c
@@ -88,6 +88,10 @@ static void print_packet(struct utcp *utcp, const char *dir, const void *pkt, si
 	if(len > sizeof hdr) {
 		uint32_t datalen = len - sizeof hdr;
 		uint8_t *str = malloc((datalen << 1) + 7);
+		if(!str) {
+			debug("out of memory");
+			return;
+		}
 		memcpy(str, " data=", 6);
 		uint8_t *strptr = str + 6;
 		const uint8_t *data = pkt;
@@ -633,7 +637,24 @@ 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)
@@ -646,13 +667,13 @@ 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;