Fix potential segmentation fault when the receive callback is not set.

A few calls to the callback function were missing a check that the
callback function pointer was non-NULL.

diff --git a/utcp.c b/utcp.c
index aa1c50f79c965709276951f992fd3e681c6feb94..f7c1859de2abe5ef05873bb1ef6565d449810e3d 100644 (file)
--- a/utcp.c
+++ b/utcp.c
@@ -1113,11 +1113,14 @@ static void handle_in_order(struct utcp_connection *c, const void *data, size_t
                        size_t offset = len;
                        len = c->sacks[0].offset + c->sacks[0].len;
                        size_t remainder = len - offset;
-                       ssize_t rxd = buffer_call(&c->rcvbuf, c->recv, c, offset, remainder);
 
-                       if(rxd != (ssize_t)remainder) {
-                               // TODO: handle the application not accepting all data.
-                               abort();
+                       if(c->recv) {
+                               ssize_t rxd = buffer_call(&c->rcvbuf, c->recv, c, offset, remainder);
+
+                               if(rxd != (ssize_t)remainder) {
+                                       // TODO: handle the application not accepting all data.
+                                       abort();
+                               }
                        }
                }
        }
@@ -1132,7 +1135,10 @@ static void handle_in_order(struct utcp_connection *c, const void *data, size_t
 static void handle_unreliable(struct utcp_connection *c, const struct hdr *hdr, const void *data, size_t len) {
        // Fast path for unfragmented packets
        if(!hdr->wnd && !(hdr->ctl & MF)) {
-               c->recv(c, data, len);
+               if(c->recv) {
+                       c->recv(c, data, len);
+               }
+
                c->rcv.nxt = hdr->seq + len;
                return;
        }
@@ -1159,7 +1165,7 @@ static void handle_unreliable(struct utcp_connection *c, const struct hdr *hdr,
        }
 
        // Send the packet if it's the final fragment
-       if(!(hdr->ctl & MF)) {
+       if(!(hdr->ctl & MF) && c->recv) {
                buffer_call(&c->rcvbuf, c->recv, c, 0, hdr->wnd + len);
        }