Ensure we retransmit the SYNACK packet if we didn't get an ACK back for it.

We didn't start the retransmission timer when we got an incoming connection,
and we didn't send an ACK back when we received a retransmitted SYNACK
without any data.

diff --git a/utcp.c b/utcp.c
index 5eca4d3897a82eec6bbc1bca6de33c324fb73daa..47acf221318bca518eca4d88bdd7ba04b0982071 100644 (file)
--- a/utcp.c
+++ b/utcp.c
@@ -890,7 +890,7 @@ static void retransmit(struct utcp_connection *c) {
 
        struct utcp *utcp = c->utcp;
 
-       if (utcp->retransmit) {
+       if(utcp->retransmit) {
                utcp->retransmit(c);
        }
 
@@ -1352,6 +1352,8 @@ synack:
                                print_packet(c, "send", &pkt, sizeof(hdr));
                                utcp->send(utcp, &pkt, sizeof(hdr));
                        }
+
+                       start_retransmit_timer(c);
                } else {
                        // No, we don't want your packets, send a RST back
                        len = 1;
@@ -1713,7 +1715,7 @@ skip_ack:
                        }
 
                        c->rcv.irs = hdr.seq;
-                       c->rcv.nxt = hdr.seq;
+                       c->rcv.nxt = hdr.seq + 1;
 
                        if(c->shut_wr) {
                                c->snd.last++;
@@ -1722,7 +1724,6 @@ skip_ack:
                                set_state(c, ESTABLISHED);
                        }
 
-                       // TODO: notify application of this somehow.
                        break;
 
                case SYN_RECEIVED:
@@ -1736,8 +1737,8 @@ skip_ack:
                case CLOSING:
                case LAST_ACK:
                case TIME_WAIT:
-                       // Ehm, no. We should never receive a second SYN.
-                       return 0;
+                       // This could be a retransmission. Ignore the SYN flag, but send an ACK back.
+                       break;
 
                default:
 #ifdef UTCP_DEBUG
@@ -1745,9 +1746,6 @@ skip_ack:
 #endif
                        return 0;
                }
-
-               // SYN counts as one sequence number
-               c->rcv.nxt++;
        }
 
        // 6. Process new data