Always check the return value of malloc().

[utcp] / utcp.c

diff --git a/utcp.c b/utcp.c
index 89a38b7d1c9546e94458531031b2ea419dad9cd6..95a82c428710ca91f5f2752045eea036bee40c79 100644 (file)
--- 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;
@@ -547,8 +551,11 @@ 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 +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)
@@ -643,13 +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;